Paperclip::Railtie.insert should be wrapped in a initializer block

lib/paperclip/railtie.rb

@@ -4,8 +4,10 @@ module Paperclip
   if defined? Rails::Railtie
     require 'rails'
     class Railtie < Rails::Railtie
-      ActiveSupport.on_load :active_record do
-        Paperclip::Railtie.insert
+      initializer 'paperclip.insert_into_active_record' do
+        ActiveSupport.on_load :active_record do
+          Paperclip::Railtie.insert
+        end
       end
       rake_tasks do
         load "tasks/paperclip.rake"