### Manage config.secret_token with environment variable
Put this in your rails app’s Gemfile:
gem 'rails_secret_token_env'
This will set your app’s config.secret_token to the SECRET_TOKEN environment variable.
In production mode, it will raise an error if the variable is missing. (In development mode, it will default to ‘xxxxxx’ if not found)
See also: gem ‘dotenv’