Remove rails_12factor (#2901)

Gemfile

@@ -98,6 +98,5 @@ end
 
 group :production do
   gem 'lograge'
-  gem 'rails_12factor'
   gem 'redis-rails'
 end

Gemfile.lock

@@ -318,11 +318,6 @@ GEM
       railties (~> 5.0)
     rails-settings-cached (0.6.5)
       rails (>= 4.2.0)
-    rails_12factor (0.0.3)
-      rails_serve_static_assets
-      rails_stdout_logging
-    rails_serve_static_assets (0.0.5)
-    rails_stdout_logging (0.0.5)
     railties (5.0.2)
       actionpack (= 5.0.2)
       activesupport (= 5.0.2)
@@ -528,7 +523,6 @@ DEPENDENCIES
   rails-controller-testing
   rails-i18n
   rails-settings-cached
-  rails_12factor
   redis (~> 3.2)
   redis-namespace
   redis-rails

config/environments/production.rb

@@ -19,6 +19,11 @@ Rails.application.configure do
   # Apache or NGINX already handles this.
   config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
 
+  ActiveSupport::Logger.new(STDOUT).tap do |logger|
+    logger.formatter = config.log_formatter
+    config.logger = ActiveSupport::TaggedLogging.new(logger)
+  end
+
   # Compress JavaScripts and CSS.
   config.assets.js_compressor = Uglifier.new(mangle: false)
   # config.assets.css_compressor = :sass