Update application.rb file for rails4

config/application.rb

@@ -1,11 +1,13 @@
 require File.expand_path('../boot', __FILE__)
 
-require 'rails/all'
+require "active_record/railtie"
+require "action_controller/railtie"
+require "action_mailer/railtie"
+require "sprockets/railtie"
 
-# If you have a Gemfile, require the default gems, the ones in the
-# current environment and also include :assets gems if in development
-# or test environments.
-Bundler.require *Rails.groups(:assets) if defined?(Bundler)
+# Require the gems listed in Gemfile, including any gems
+# you've limited to :test, :development, or :production.
+Bundler.require(:default, Rails.env)
 
 module Prometheus20
   class Application < Rails::Application
@@ -17,13 +19,6 @@ class Application < Rails::Application
     # config.autoload_paths += %W(#{config.root}/extras)
     config.autoload_paths += %W(#{config.root}/lib)
 
-    # Only load the plugins named here, in the order given (default is alphabetical).
-    # :all can be used as a placeholder for all plugins not explicitly named.
-    # config.plugins = [ :exception_notification, :ssl_requirement, :all ]
-
-    # Activate observers that should always be running.
-    # config.active_record.observers = :cacher, :garbage_collector, :forum_observer
-
     # Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
     # Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
     # config.time_zone = 'Central Time (US & Canada)'