Use Rails::Queueing::Queue instead of Queue so people can build their own consumers around stdlib's Queue

railties/lib/rails/application/configuration.rb

@@ -43,7 +43,7 @@ module Rails
         @autoflush_log                 = true
         @log_formatter                 = ActiveSupport::Logger::SimpleFormatter.new
         @use_schema_cache_dump         = true
-        @queue                         = Queue
+        @queue                         = Rails::Queueing::Queue
 
         @assets = ActiveSupport::OrderedOptions.new
         @assets.enabled                  = false

railties/lib/rails/application/finisher.rb

@@ -95,7 +95,7 @@ module Rails
       end
 
       initializer :activate_queue_consumer do |app|
-        if config.queue == Queue
+        if config.queue == Rails::Queueing::Queue
           consumer = Rails::Queueing::ThreadedConsumer.start(app.queue)
           at_exit { consumer.shutdown }
         end

railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt

@@ -37,5 +37,5 @@
   <%- end -%>
 
   # In development, use an in-memory queue for queueing
-  config.queue = Queue
+  config.queue = Rails::Queueing::Queue
 end

railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt

@@ -79,5 +79,5 @@
 
   # Default the production mode queue to an in-memory queue. You will probably
   # want to replace this with an out-of-process queueing solution
-  config.queue = Queue
+  config.queue = Rails::Queueing::Queue
 end

railties/lib/rails/queueing.rb

@@ -1,5 +1,13 @@
+require "thread"
+
 module Rails
   module Queueing
+    # A Queue that simply inherits from STDLIB's Queue. Everytime this
+    # queue is used, Rails automatically sets up a ThreadedConsumer
+    # to consume it.
+    class Queue < ::Queue
+    end
+
     # In test mode, the Rails queue is backed by an Array so that assertions
     # can be made about its contents. The test queue provides a +jobs+
     # method to make assertions about the queue's contents and a +drain+

railties/test/application/queue_test.rb

@@ -26,8 +26,8 @@ module ApplicationTests
 
     test "the queue is a Queue in development mode" do
       app("development")
-      assert_kind_of Queue, Rails.application.queue
-      assert_kind_of Queue, Rails.queue
+      assert_kind_of Rails::Queueing::Queue, Rails.application.queue
+      assert_kind_of Rails::Queueing::Queue, Rails.queue
     end
 
     test "in development mode, an enqueued job will be processed in a separate thread" do

railties/test/queueing/threaded_consumer_test.rb

@@ -15,7 +15,7 @@ class TestThreadConsumer < ActiveSupport::TestCase
   end
 
   def setup
-    @queue = Queue.new
+    @queue = Rails::Queueing::Queue.new
     @consumer = Rails::Queueing::ThreadedConsumer.start(@queue)
   end