production環境でsecret_tokenをセットする(rails)

config/secrets.ymlにてsecret_key_baseを設定しないと
『app error: Missing secret_token and secret_key_base for 'production' environment, set these values in config/secrets.yml (RuntimeError)』
と怒られる。

production環境でsecret_key_baseをセットする方法

config/secrets.ymlの中身

secrets.yml

# Be sure to restart your server when you modify this file.

# Your secret key is used for verifying the integrity of signed cookies.
# If you change this key, all old signed cookies will become invalid!

# Make sure the secret is at least 30 characters and all random,
# no regular words or you'll be exposed to dictionary attacks.
# You can use `rake secret` to generate a secure secret key.

# Make sure the secrets in this file are kept private
# if you're sharing your code publicly.

development:
  secret_key_base: aca69c863386b8b18bea7baef237fc1f5c7328d4765abf04de32119de7c6c5f1b7880a7bc259a455fd9659494c2b2a799ba285b4e5581322f919cc2f5d544354

test:
  secret_key_base: 47df8937b0b175ae7c5e297c69153c7cb0e675e6ad485039cbd9313b8ba39a41259d4ccef4f5c8033db20b643ab0dd687808bc8503750c6c87968711ca4

# Do not keep production secrets in the repository,
# instead read values from the environment.
production:
  secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>

keyを生成

$ bundle exec rake secret
qnaiglfmugm82487yfam7y4qixm8734pt7bfdac6622iou9x74pof904r77ed64ba5a8c4r3qoi5u948x3q7n0q98q7089qm398

環境変数に設定

$export SECRET_KEY_BASE=
qnaiglfmugm82487yfam7y4qixm8734pt7bfdac6622iou9x74pof904r77ed64ba5a8c4r3qoi5u948x3q7n0q98q7089qm398

これでOK