docker-compose run web rails db:migrateでエラーが出る

エラー内容　

[+] Running 1/0
 ⠿ Container sample_app_local-db-1  Running                                                                                                  0.0s
Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
Couldn't create 'sample_app_development' database. Please check your configuration.
rails aborted!
ActiveRecord::ConnectionNotEstablished: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
/myapp/bin/rails:5:in `<top (required)>'
/myapp/bin/spring:15:in `<top (required)>'

Caused by:
Mysql2::Error::ConnectionError: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
/myapp/bin/rails:5:in `<top (required)>'
/myapp/bin/spring:15:in `<top (required)>'
Tasks: TOP => db:create
(See full trace by running task with --trace)

該当のソースコード　

docker-compose.yml

version: "3"
services:
  web:
    container_name:  sample_app_local
    build: .
    command: bash -c "rm -f tmp/pids/server.pid && yarn install && bundle exec rails s -p 3000 -b '0.0.0.0'"
    volumes:
      - .:/myapp
    ports:
      - "3000:3000"
    depends_on:
      - db
  
  db:
    image: mysql:5.7
    volumes:
      - mysql-data:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: password
      MYSQL_USER: root
    ports:
      - 3306:3306

volumes:
  mysql-data:

config/database.yml

#該当箇所を抜粋
default: &default
  adapter: mysql2
  encoding: utf8
  charset: utf8
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  username: root
  password: password
  socket: /tmp/mysql.sock

原因・解決

database.yml に host の設定が抜けていたから

config/database.yml

default: &default
  adapter: mysql2
  encoding: utf8
  charset: utf8
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  username: root
  password: password
  socket: /tmp/mysql.sock
  host: db                    #追記

参考サイト　

dockerでのエラー　Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)　を解決