Be consisent in usage of ActiveSupport::Autoload

Author: bf4

lib/active_model_serializers/test.rb

@@ -1,5 +1,6 @@
 module ActiveModelSerializers
   module Test
-    autoload :Serializer, 'active_model_serializers/test/serializer'
+    extend ActiveSupport::Autoload
+    autoload :Serializer
   end
 end