1 files changed, 15 insertions, 1 deletions
diff --git a/railties/lib/rails.rb b/railties/lib/rails.rb
index ecd8c22dd8..a1a105ef2b 100644
--- a/railties/lib/rails.rb
+++ b/railties/lib/rails.rb
@@ -29,7 +29,13 @@ module Rails
   autoload :WelcomeController
 
   class << self
-    attr_accessor :application, :cache, :logger
+    @application = @app_class = nil
+
+    attr_writer :application
+    attr_accessor :app_class, :cache, :logger
+    def application
+      @application ||= (app_class.instance if app_class)
+    end
 
     delegate :initialize!, :initialized?, to: :application
 
@@ -50,10 +56,18 @@ module Rails
       application && application.config.root
     end
 
+    # Returns the current Rails environment.
+    #
+    #   Rails.env # => "development"
+    #   Rails.env.development? # => true
+    #   Rails.env.production? # => false
     def env
       @_env ||= ActiveSupport::StringInquirer.new(ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "development")
     end
 
+    # Sets the Rails environment.
+    #
+    #   Rails.env = "staging" # => "staging"
     def env=(environment)
       @_env = ActiveSupport::StringInquirer.new(environment)
     end