#解決策

heroku run rake db:migrate RAILS_ENV=production
エラー
↓
heroku run rake db:reset RAILS_ENV=production
↓
heroku run rake db:reset RAILS_ENV=production DISABLE_DATABASE_ENVIRONMENT_CHECK=1

asatokensei@MacBook-Air memopy % heroku run rake db:migrate RAILS_ENV=production                        
Running rake db:migrate RAILS_ENV=production on ⬢ memopy... up, run.8417 (Free)
/app/vendor/bundle/ruby/2.7.0/gems/actionpack-5.2.4.3/lib/action_dispatch/middleware/stack.rb:37: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/actionpack-5.2.4.3/lib/action_dispatch/middleware/static.rb:111: warning: The called method `initialize' is defined here
D, [2020-07-19T01:46:02.234093 #4] DEBUG -- :    (10.4ms)  SET NAMES utf8,  @@SESSION.sql_mode = CONCAT(CONCAT(@@sql_mode, ',STRICT_ALL_TABLES'), ',NO_AUTO_VALUE_ON_ZERO'),  @@SESSION.sql_auto_is_null = 0, @@SESSION.wait_timeout = 2147483
D, [2020-07-19T01:46:02.309138 #4] DEBUG -- :    (7.4ms)  SELECT GET_LOCK('3493520402598712500', 0)
D, [2020-07-19T01:46:02.343777 #4] DEBUG -- :    (4.5ms)  SELECT `schema_migrations`.`version` FROM `schema_migrations` ORDER BY `schema_migrations`.`version` ASC
I, [2020-07-19T01:46:02.355197 #4]  INFO -- : Migrating to CreateUsers (20200622082810)
== 20200622082810 CreateUsers: migrating ======================================
-- create_table(:users)
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/mysql/schema_statements.rb:78: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_definitions.rb:263: warning: The called method `initialize' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:301: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_definitions.rb:204: warning: The called method `primary_key' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_definitions.rb:366: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/mysql/schema_definitions.rb:55: warning: The called method `new_column_definition' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_creation.rb:19: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:448: warning: The called method `type_to_sql' is defined here
D, [2020-07-19T01:46:02.394757 #4] DEBUG -- :    (13.5ms)  CREATE TABLE `users` (`id` bigint NOT NULL AUTO_INCREMENT PRIMARY KEY, `name` varchar(255), `email` varchar(255), `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL)
D, [2020-07-19T01:46:02.404327 #4] DEBUG -- :    (8.3ms)  SELECT RELEASE_LOCK('3493520402598712500')
rake aborted!
StandardError: An error has occurred, all later migrations canceled:

Mysql2::Error: Table 'users' already exists: CREATE TABLE `users` (`id` bigint NOT NULL AUTO_INCREMENT PRIMARY KEY, `name` varchar(255), `email` varchar(255), `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL)
~

Caused by:
ActiveRecord::StatementInvalid: Mysql2::Error: Table 'users' already exists: CREATE TABLE `users` (`id` bigint NOT NULL AUTO_INCREMENT PRIMARY KEY, `name` varchar(255), `email` varchar(255), `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL)
/app/vendor/bundle/ruby/2.7.0/gems/mysql2-0.5.3/lib/mysql2/client.rb:131:in `_query'
~

Caused by:
Mysql2::Error: Table 'users' already exists
/app/vendor/bundle/ruby/2.7.0/gems/mysql2-0.5.3/lib/mysql2/client.rb:131:in `_query'
~

/app/bin/bundle:3:in `<main>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

asatokensei@MacBook-Air memopy % heroku run rake db:reset RAILS_ENV=production
Running rake db:reset RAILS_ENV=production on ⬢ memopy... up, run.6452 (Free)
/app/vendor/bundle/ruby/2.7.0/gems/actionpack-5.2.4.3/lib/action_dispatch/middleware/stack.rb:37: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/actionpack-5.2.4.3/lib/action_dispatch/middleware/static.rb:111: warning: The called method `initialize' is defined here
D, [2020-07-19T01:46:43.752622 #4] DEBUG -- :    (3.5ms)  SET NAMES utf8,  @@SESSION.sql_mode = CONCAT(CONCAT(@@sql_mode, ',STRICT_ALL_TABLES'), ',NO_AUTO_VALUE_ON_ZERO'),  @@SESSION.sql_auto_is_null = 0, @@SESSION.wait_timeout = 2147483
D, [2020-07-19T01:46:43.810885 #4] DEBUG -- :    (2.8ms)  SELECT `schema_migrations`.`version` FROM `schema_migrations` ORDER BY `schema_migrations`.`version` ASC
D, [2020-07-19T01:46:43.826800 #4] DEBUG -- :    (2.9ms)  SELECT `ar_internal_metadata`.`value` FROM `ar_internal_metadata` WHERE `ar_internal_metadata`.`key` = 'environment'
D, [2020-07-19T01:46:43.834609 #4] DEBUG -- :    (4.2ms)  SELECT `schema_migrations`.`version` FROM `schema_migrations` ORDER BY `schema_migrations`.`version` ASC
D, [2020-07-19T01:46:43.840994 #4] DEBUG -- :    (2.9ms)  SELECT `ar_internal_metadata`.`value` FROM `ar_internal_metadata` WHERE `ar_internal_metadata`.`key` = 'environment'
D, [2020-07-19T01:46:43.847339 #4] DEBUG -- :    (2.9ms)  SELECT `schema_migrations`.`version` FROM `schema_migrations` ORDER BY `schema_migrations`.`version` ASC
D, [2020-07-19T01:46:43.858665 #4] DEBUG -- :    (2.9ms)  SELECT `ar_internal_metadata`.`value` FROM `ar_internal_metadata` WHERE `ar_internal_metadata`.`key` = 'environment'
rake aborted!
ActiveRecord::ProtectedEnvironmentError: You are attempting to run a destructive action against your 'production' database.
If you are sure you want to continue, run the same command with the environment variable:
DISABLE_DATABASE_ENVIRONMENT_CHECK=1
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/tasks/database_tasks.rb:61:in `check_protected_environments!'
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/railties/databases.rake:13:in `block (2 levels) in <main>'
/app/vendor/bundle/ruby/2.7.0/gems/rake-13.0.1/exe/rake:27:in `<top (required)>'
/app/bin/bundle:3:in `load'
/app/bin/bundle:3:in `<main>'
Tasks: TOP => db:reset => db:drop => db:check_protected_environments
(See full trace by running task with --trace)

DISABLE_DATABASE_ENVIRONMENT_CHECK=1
を環境変数につけろと怒られる

asatokensei@MacBook-Air memopy % heroku run rake db:reset RAILS_ENV=production DISABLE_DATABASE_ENVIRONMENT_CHECK=1
Running rake db:reset RAILS_ENV=production DISABLE_DATABASE_ENVIRONMENT_CHECK=1 on ⬢ memopy... up, run.1003 (Free)
/app/vendor/bundle/ruby/2.7.0/gems/actionpack-5.2.4.3/lib/action_dispatch/middleware/stack.rb:37: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/actionpack-5.2.4.3/lib/action_dispatch/middleware/static.rb:111: warning: The called method `initialize' is defined here
D, [2020-07-19T01:47:19.813454 #4] DEBUG -- :    (2.4ms)  SET NAMES utf8,  @@SESSION.sql_mode = CONCAT(CONCAT(@@sql_mode, ',STRICT_ALL_TABLES'), ',NO_AUTO_VALUE_ON_ZERO'),  @@SESSION.sql_auto_is_null = 0, @@SESSION.wait_timeout = 2147483
D, [2020-07-19T01:47:19.845868 #4] DEBUG -- :    (29.8ms)  DROP DATABASE IF EXISTS `heroku_a8b1a434e18a217`
Dropped database 'heroku_a8b1a434e18a217'
D, [2020-07-19T01:47:19.888807 #4] DEBUG -- :    (3.6ms)  SET NAMES utf8,  @@SESSION.sql_mode = CONCAT(CONCAT(@@sql_mode, ',STRICT_ALL_TABLES'), ',NO_AUTO_VALUE_ON_ZERO'),  @@SESSION.sql_auto_is_null = 0, @@SESSION.wait_timeout = 2147483
D, [2020-07-19T01:47:19.897784 #4] DEBUG -- :    (5.6ms)  CREATE DATABASE `heroku_a8b1a434e18a217` DEFAULT CHARACTER SET `utf8`
Created database 'heroku_a8b1a434e18a217'
-- create_table("friends", {:options=>"ENGINE=InnoDB DEFAULT CHARSET=utf8", :force=>:cascade})
D, [2020-07-19T01:47:19.941421 #4] DEBUG -- :    (3.3ms)  SET NAMES utf8,  @@SESSION.sql_mode = CONCAT(CONCAT(@@sql_mode, ',STRICT_ALL_TABLES'), ',NO_AUTO_VALUE_ON_ZERO'),  @@SESSION.sql_auto_is_null = 0, @@SESSION.wait_timeout = 2147483
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/migration.rb:871: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:290: warning: The called method `create_table' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/mysql/schema_statements.rb:78: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_definitions.rb:263: warning: The called method `initialize' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:301: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_definitions.rb:204: warning: The called method `primary_key' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_definitions.rb:366: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/mysql/schema_definitions.rb:55: warning: The called method `new_column_definition' is defined here
D, [2020-07-19T01:47:19.950134 #4] DEBUG -- :    (5.0ms)  DROP TABLE IF EXISTS `friends` CASCADE
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_creation.rb:19: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:448: warning: The called method `type_to_sql' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/mysql/schema_creation.rb:67: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:1135: warning: The called method `add_index_options' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:1162: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:1215: warning: The called method `quoted_columns_for_index' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:1219: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/mysql/schema_statements.rb:116: warning: The called method `add_options_for_index_columns' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/mysql/schema_statements.rb:117: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/mysql/schema_statements.rb:109: warning: The called method `add_index_length' is defined here
D, [2020-07-19T01:47:19.975793 #4] DEBUG -- :    (21.7ms)  CREATE TABLE `friends` (`id` bigint NOT NULL AUTO_INCREMENT PRIMARY KEY, `name` varchar(255), `user_id` bigint, `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL,  INDEX `index_friends_on_user_id`  (`user_id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8
   -> 0.0745s
-- create_table("friends_details", {:options=>"ENGINE=InnoDB DEFAULT CHARSET=utf8", :force=>:cascade})
D, [2020-07-19T01:47:19.981422 #4] DEBUG -- :    (5.1ms)  DROP TABLE IF EXISTS `friends_details` CASCADE
D, [2020-07-19T01:47:20.004336 #4] DEBUG -- :    (18.6ms)  CREATE TABLE `friends_details` (`id` bigint NOT NULL AUTO_INCREMENT PRIMARY KEY, `feature` varchar(255), `content` varchar(255), `friend_id` bigint, `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL,  INDEX `index_friends_details_on_friend_id`  (`friend_id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8
   -> 0.0285s
-- create_table("users", {:options=>"ENGINE=InnoDB DEFAULT CHARSET=utf8", :force=>:cascade})
D, [2020-07-19T01:47:20.009874 #4] DEBUG -- :    (4.9ms)  DROP TABLE IF EXISTS `users` CASCADE
D, [2020-07-19T01:47:20.026343 #4] DEBUG -- :    (16.0ms)  CREATE TABLE `users` (`id` bigint NOT NULL AUTO_INCREMENT PRIMARY KEY, `name` varchar(255), `email` varchar(255), `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL, `password_digest` varchar(255), `remember_digest` varchar(255)) ENGINE=InnoDB DEFAULT CHARSET=utf8
   -> 0.0219s
-- add_foreign_key("friends", "users")
D, [2020-07-19T01:47:20.051596 #4] DEBUG -- :    (24.5ms)  ALTER TABLE `friends` ADD CONSTRAINT `fk_rails_9cfeeb4593`
FOREIGN KEY (`user_id`)
  REFERENCES `users` (`id`)

   -> 0.0252s
-- add_foreign_key("friends_details", "friends")
D, [2020-07-19T01:47:20.074413 #4] DEBUG -- :    (22.1ms)  ALTER TABLE `friends_details` ADD CONSTRAINT `fk_rails_9652152079`
FOREIGN KEY (`friend_id`)
  REFERENCES `friends` (`id`)

   -> 0.0227s
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/schema_migration.rb:30: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_definitions.rb:231: warning: The called method `string' is defined here
D, [2020-07-19T01:47:20.141107 #4] DEBUG -- :    (18.0ms)  CREATE TABLE `schema_migrations` (`version` varchar(255) NOT NULL PRIMARY KEY)
D, [2020-07-19T01:47:20.164256 #4] DEBUG -- :    (3.7ms)  SELECT `schema_migrations`.`version` FROM `schema_migrations` ORDER BY `schema_migrations`.`version` ASC
D, [2020-07-19T01:47:20.181513 #4] DEBUG -- :    (11.7ms)  INSERT INTO `schema_migrations` (version) VALUES (20200703094957)
D, [2020-07-19T01:47:20.195092 #4] DEBUG -- :    (13.2ms)  INSERT INTO `schema_migrations` (version) VALUES
(20200622082810),
(20200625044306),
(20200628063636),
(20200622105712);


/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/internal_metadata.rb:37: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/schema_definitions.rb:231: warning: The called method `string' is defined here
D, [2020-07-19T01:47:20.221338 #4] DEBUG -- :    (16.8ms)  CREATE TABLE `ar_internal_metadata` (`key` varchar(255) NOT NULL PRIMARY KEY, `value` varchar(255), `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL)
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/mysql/database_statements.rb:12: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/query_cache.rb:95: warning: The called method `select_all' is defined here
D, [2020-07-19T01:47:20.235618 #4] DEBUG -- :   ActiveRecord::InternalMetadata Load (3.8ms)  SELECT  `ar_internal_metadata`.* FROM `ar_internal_metadata` WHERE `ar_internal_metadata`.`key` = 'environment' LIMIT 1
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/transactions.rb:212: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/database_statements.rb:260: warning: The called method `transaction' is defined here
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/transaction.rb:171: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/connection_adapters/abstract/transaction.rb:97: warning: The called method `initialize' is defined here
D, [2020-07-19T01:47:20.282497 #4] DEBUG -- :    (3.6ms)  BEGIN
D, [2020-07-19T01:47:20.287857 #4] DEBUG -- :   ActiveRecord::InternalMetadata Create (3.4ms)  INSERT INTO `ar_internal_metadata` (`key`, `value`, `created_at`, `updated_at`) VALUES ('environment', 'production', '2020-07-19 01:47:20', '2020-07-19 01:47:20')
D, [2020-07-19T01:47:20.297353 #4] DEBUG -- :    (9.1ms)  COMMIT
D, [2020-07-19T01:47:20.305087 #4] DEBUG -- :   ActiveRecord::InternalMetadata Load (3.5ms)  SELECT  `ar_internal_metadata`.* FROM `ar_internal_metadata` WHERE `ar_internal_metadata`.`key` = 'environment' LIMIT 1
D, [2020-07-19T01:47:20.309743 #4] DEBUG -- :    (3.2ms)  BEGIN
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/persistence.rb:705: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/app/vendor/bundle/ruby/2.7.0/gems/activerecord-5.2.4.3/lib/active_record/timestamp.rb:105: warning: The called method `_update_record' is defined here
D, [2020-07-19T01:47:20.317225 #4] DEBUG -- :    (3.3ms)  COMMIT
D, [2020-07-19T01:47:20.386050 #4] DEBUG -- :    (3.4ms)  SET NAMES utf8,  @@SESSION.sql_mode = CONCAT(CONCAT(@@sql_mode, ',STRICT_ALL_TABLES'), ',NO_AUTO_VALUE_ON_ZERO'),  @@SESSION.sql_auto_is_null = 0, @@SESSION.wait_timeout = 2147483
D, [2020-07-19T01:47:20.408582 #4] DEBUG -- :    (4.1ms)  SELECT `schema_migrations`.`version` FROM `schema_migrations` ORDER BY `schema_migrations`.`version` ASC

#参考記事
https://qiita.com/Atsushi_/items/a230fb7f624d1eebf2f3