[ActiveJob] Autoload adapters

activejob/lib/active_job.rb

@@ -30,4 +30,5 @@ module ActiveJob
   extend ActiveSupport::Autoload
 
   autoload :Base
-end
+  autoload :QueueAdapters
+end

activejob/lib/active_job/queue_adapter.rb

@@ -17,7 +17,6 @@ def queue_adapter=(name_or_adapter)
 
     private
       def load_adapter(name)
-        require "active_job/queue_adapters/#{name}_adapter"
         "ActiveJob::QueueAdapters::#{name.to_s.camelize}Adapter".constantize
       end
   end

activejob/lib/active_job/queue_adapters.rb

@@ -0,0 +1,16 @@
+module ActiveJob
+  module QueueAdapters
+    extend ActiveSupport::Autoload
+
+    autoload :InlineAdapter
+    autoload :BackburnerAdapter
+    autoload :DelayedJobAdapter
+    autoload :QuAdapter
+    autoload :QueAdapter
+    autoload :QueueClassicAdapter
+    autoload :ResqueAdapter
+    autoload :SidekiqAdapter
+    autoload :SneakersAdapter
+    autoload :SuckerPunchAdapter
+  end
+end