Remove the queue configuration from the environments templates since the

default is the SynchronousQueue.

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

@@ -41,7 +41,4 @@
   # Debug mode disables concatenation and preprocessing of assets.
   config.assets.debug = true
   <%- end -%>
-
-  # In development, use an synchronous queue for queueing.
-  config.queue = Rails::Queueing::SynchronousQueue
 end

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

@@ -82,5 +82,5 @@
 
   # Default the production mode queue to an synchronous queue. You will probably
   # want to replace this with an out-of-process queueing solution.
-  config.queue = Rails::Queueing::SynchronousQueue
+  # config.queue = Rails::Queueing::SynchronousQueue
 end