modify rubocop to warn when no trailing comma
move cookies_serializer initializer to its own file
File.exists? -> File.exist?
update environment.rb
regenerate config/initializers/mime_types.rb
update config/initializers/session_store.rb
regenerate config/environments/test.rb
regenerate config/environments/development.rb
regenerate config/environments/production.rb
Merge branch 'feature/update-rails-config'