Drop rails_12factor gem

Use the proposed rails 5 environment variables instead.

Gemfile

@@ -15,11 +15,6 @@ gem 'rails', '~> 5.0.7'
 # Use Puma as the app server
 gem 'puma', '~> 3.0'
 
-# enables serving assets in production and setting your logger to standard out
-# both of which are required to run an application on a twelve-factor provider
-# like heroku.com
-gem 'rails_12factor', group: :production
-
 # respond_to methods have been extracted to the responders gem
 # http://edgeguides.rubyonrails.org/upgrading_ruby_on_rails.html#responders
 gem 'responders', '~> 2.0'

Gemfile.lock

@@ -426,11 +426,6 @@ GEM
     rails-i18n (5.0.4)
       i18n (~> 0.7)
       railties (~> 5.0)
-    rails_12factor (0.0.3)
-      rails_serve_static_assets
-      rails_stdout_logging
-    rails_serve_static_assets (0.0.4)
-    rails_stdout_logging (0.0.3)
     railties (5.0.7.1)
       actionpack (= 5.0.7.1)
       activesupport (= 5.0.7.1)
@@ -693,7 +688,6 @@ DEPENDENCIES
   rails-assets-waypoints!
   rails-controller-testing
   rails-i18n (~> 5.0.0)
-  rails_12factor
   rdoc-generator-fivefish
   recaptcha
   redcarpet

config/environments/production.rb

@@ -43,10 +43,17 @@ Osem::Application.configure do
   config.log_level = ENV['OSEM_LOG_LEVEL'].try(:to_sym) || :info
 
   # Prepend all log lines with the following tags
-  # config.log_tags = [ :subdomain, :uuid ]
+  config.log_tags = [:uuid]
 
-  # Use a different logger for distributed setups
-  # config.logger = ActiveSupport::TaggedLogging.new(SyslogLogger.new)
+  # Disable serving static files from the `/public` folder by default since
+  # Apache or NGINX already handles this.
+  config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
+
+  if ENV["RAILS_LOG_TO_STDOUT"].present?
+    logger           = ActiveSupport::Logger.new(STDOUT)
+    logger.formatter = config.log_formatter
+    config.logger = ActiveSupport::TaggedLogging.new(logger)
+  end
 
   # Use a different cache store in production
   # config.cache_store = :mem_cache_store