Refactor of ::Rails module

1. Used ActiveSupport::Autoload to dry-up the autoload definitions.
2. Used ActiveSupport's delegate to dry up the application proxied
   attributes.
3. Did a little white space change on Rails.groups.

railties/lib/rails.rb

@@ -3,7 +3,9 @@
 require 'pathname'
 
 require 'active_support'
+require 'active_support/dependencies/autoload'
 require 'active_support/core_ext/kernel/reporting'
+require 'active_support/core_ext/module/delegation'
 require 'active_support/core_ext/array/extract_options'
 
 require 'rails/application'
@@ -20,26 +22,22 @@
 end
 
 module Rails
-  autoload :Info, 'rails/info'
-  autoload :InfoController,    'rails/info_controller'
-  autoload :WelcomeController, 'rails/welcome_controller'
+  extend ActiveSupport::Autoload
+
+  autoload :Info
+  autoload :InfoController
+  autoload :WelcomeController
 
   class << self
     attr_accessor :application, :cache, :logger
 
+    delegate :initialize!, :initialized?, to: :application
+
     # The Configuration instance used to configure the Rails environment
     def configuration
       application.config
     end
 
-    def initialize!
-      application.initialize!
-    end
-
-    def initialized?
-      application.initialized?
-    end
-
     def backtrace_cleaner
       @backtrace_cleaner ||= begin
         # Relies on Active Support, so we have to lazy load to postpone definition until AS has been loaded
@@ -76,7 +74,7 @@ def groups(*groups)
       env = Rails.env
       groups.unshift(:default, env)
       groups.concat ENV["RAILS_GROUPS"].to_s.split(",")
-      groups.concat hash.map { |k,v| k if v.map(&:to_s).include?(env) }
+      groups.concat hash.map { |k, v| k if v.map(&:to_s).include?(env) }
       groups.compact!
       groups.uniq!
       groups