[ActiveJob] Add queue_name_prefix so all queue are prefixed .

We can split queues on a per environement basis as well as seggregate per application so we can split queues on a per env basis

ActiveJob::Base.queue_name_prefix = 'foo'

activejob/lib/active_job/queue_name.rb

@@ -3,10 +3,13 @@ module QueueName
     extend ActiveSupport::Concern
 
     module ClassMethods
+      mattr_accessor(:queue_name_prefix)
       mattr_accessor(:default_queue_name) { "default" }
 
       def queue_as(part_name)
-        self.queue_name = part_name.to_s.presence || default_queue_name
+        queue_name = part_name.to_s.presence || default_queue_name
+        name_parts = [queue_name_prefix.presence, queue_name]
+        self.queue_name = name_parts.compact.join('_')
       end
     end
 

activejob/test/cases/queue_naming_test.rb

@@ -20,4 +20,19 @@ class QueueNamingTest < ActiveSupport::TestCase
       HelloJob.queue_name = LoggingJob.queue_name = ActiveJob::Base.default_queue_name
     end
   end
+
+  test 'should prefix the queue name' do
+    begin
+      original_queue_name_prefix = ActiveJob::Base.queue_name_prefix
+      original_queue_name = HelloJob.queue_name
+
+      ActiveJob::Base.queue_name_prefix = 'aj'
+      HelloJob.queue_as :low
+      assert_equal 'aj_low', HelloJob.queue_name
+    ensure
+      ActiveJob::Base.queue_name_prefix = original_queue_name_prefix
+      HelloJob.queue_name = original_queue_name
+    end
+  end
+
 end