Require only required railties

config/application.rb

@@ -1,6 +1,12 @@
 require File.expand_path('../boot', __FILE__)
 
-require 'rails/all'
+require 'rails'
+# Pick the frameworks you want:
+require 'active_model/railtie'
+require 'active_record/railtie'
+require 'action_controller/railtie'
+require 'action_mailer/railtie'
+require 'action_view/railtie'
 
 # Require the gems listed in Gemfile, including any gems
 # you've limited to :test, :development, or :production.