undefined method "load_paths" for ActiveSupport::Dependencies:Module Error

I'm writing a Rails plugin from scratch and recently generating models inside it. In fact, i'm trying to follow the guide from The Basics of Creating Rails Plugins — Ruby on Rails Guides so i used the following code taken from this site in order to make the models appear like files in the main app directory (as it was said)

this is the code: %w{ models }.each do |dir|   path = File.join(File.dirname(__FILE__), 'app', dir)   $LOAD_PATH << path   ActiveSupport::Dependencies.load_paths << path   ActiveSupport::Dependencies.load_once_paths.delete(path) end