Drop Rails.application.secrets usage

That feature is gone and we already use environment variables...

https://github.com/rails/rails/pull/47801

config/initializers/devise.rb

@@ -7,11 +7,9 @@ Devise.setup do |config|
   # Pass each provider to User model in :omniauth_providers (for open_id providers use their name)
 
   config.omniauth :open_id, name: 'suse', identifier: 'http://www.opensuse.org/openid/user'
-  config.omniauth :google_oauth2, ENV.fetch('OSEM_GOOGLE_KEY', Rails.application.secrets.google_key), ENV.fetch('OSEM_GOOGLE_SECRET', Rails.application.secrets.google_secret),
-                  name:  'google',
-                  scope: 'email'
-  config.omniauth :facebook, ENV.fetch('OSEM_FACEBOOK_KEY', Rails.application.secrets.facebook_key), ENV.fetch('OSEM_FACEBOOK_SECRET', Rails.application.secrets.facebook_secret)
-  config.omniauth :github, ENV.fetch('OSEM_GITHUB_KEY', Rails.application.secrets.github_key), ENV.fetch('OSEM_GITHUB_SECRET', Rails.application.secrets.github_secret)
+  config.omniauth :google_oauth2, ENV.fetch('OSEM_GOOGLE_KEY', nil), ENV.fetch('OSEM_GOOGLE_SECRET', nil), name: 'google', scope: 'email'
+  config.omniauth :facebook, ENV.fetch('OSEM_FACEBOOK_KEY', nil), ENV.fetch('OSEM_FACEBOOK_SECRET', nil)
+  config.omniauth :github, ENV.fetch('OSEM_GITHUB_KEY', nil), ENV.fetch('OSEM_GITHUB_SECRET', nil)
 
   # ==> Mailer Configuration
   # Configure the e-mail address which will be shown in Devise::Mailer,

config/initializers/sentry.rb

@@ -1,5 +1,5 @@
 Sentry.init do |config|
-  config.dsn = ENV.fetch('OSEM_SENTRY_DSN', Rails.application.secrets.sentry_dsn)
+  config.dsn = ENV.fetch('OSEM_SENTRY_DSN', nil)
   config.breadcrumbs_logger = [:active_support_logger]
 
   # To activate performance monitoring, set one of these options.

config/initializers/stripe.rb

@@ -1 +1 @@
-Stripe.api_key = Rails.application.secrets.stripe_secret_key
+Stripe.api_key = ENV.fetch('STRIPE_SECRET_KEY', nil)

config/secrets.yml.example

@@ -1,73 +0,0 @@
-development:
-  # Generate your own with rake secret
-  # secret_key_base: '12345'
-
-  ########## OMNIAUTH Providers ##########
-  # This is just sample data so mocks work
-  google_key: 'sample'
-  google_secret: 'sample'
-
-  facebook_key: 'sample'
-  facebook_secret: 'sample'
-
-  suse_key: 'sample'
-  suse_secret: 'sample'
-
-  # Register on stripe and add TEST keys here
-  # https://dashboard.stripe.com/account/apikeys
-  stripe_publishable_key: <%= ENV['STRIPE_PUBLISHABLE_KEY'] %>
-  stripe_secret_key: <%= ENV['STRIPE_SECRET_KEY'] %>
-
-test:
-  # Generate your own with rake secret
-  # secret_key_base: '12345'
-
-  # Register on stripe and add TEST keys here
-  # https://dashboard.stripe.com/account/apikeys
-  stripe_publishable_key: <%= ENV['STRIPE_PUBLISHABLE_KEY'] %>
-  stripe_secret_key: <%= ENV['STRIPE_SECRET_KEY'] %>
-
-production:
-  # Generate your own with rake secret or use the environment
-  # secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>
-
-  # Your sentry.io DSN key
-  # sentry_dsn: '12345'
-
-  ########## OMNIAUTH Providers ##########
-  # Leave the variables' names empty, unless you use the providers, in which
-  # case you need to register your applicaton and add the actual keys.
-  #
-  # If you add a provider, keep the format of the variables:
-  # *provider*_key and *provider*_secret
-
-  # If you add a provider that does not require a key, you still have to
-  # create the 2 variables with sample data or they won't show up in the app.
-
-  # Register your appllication with Google from
-  # https://code.google.com/apis/console#:access
-  google_key: ''
-  google_secret: ''
-
-  # Register your application with Facebook from
-  # https://developers.facebook.com/
-  facebook_key: ''
-  facebook_secret: ''
-
-  # Developers do not need to register their application for suse account to
-  # work. You must, however, add some sample value to the variables, for the
-  # login option to appear. For example:
-  #suse_key: 'sample data'
-  #suse_secret: 'sample data'
-  suse_key: ''
-  suse_secret: ''
-
-  # Register your application with GitHub from
-  # https://github.com/settings/applications
-  github_key: ''
-  github_secret: ''
-
-  # Register on stripe and add LIVE keys here
-  # https://dashboard.stripe.com/account/apikeys
-  stripe_publishable_key: <%= ENV['STRIPE_PUBLISHABLE_KEY'] %>
-  stripe_secret_key: <%= ENV['STRIPE_SECRET_KEY'] %>