Named_scope common for all active record models

While i was doing my project in REST Architecture, i used some named_scope in models.Later i saw some of the named_scope like

named_scope :limit, lambda {|limit| {:limit => limit}}

Then after a long search in Google.I started created a module in lib folder, and i had my common named_scope.Then i started calling the module in my models.

module CommonScopes
def self.included(base)
base.class_eval do
named_scope :limit, lambda {|limit| {:limit => limit}}
named_scope :include_user,:include=>:user
end
end
end

ActiveRecord models

class Forum < ActiveRecord::Base has_many:topics, :dependent=>:delete_all
has_many:posts, :through=>:topics

validates_presence_of :name
validates_length_of :name, :maximum => 255
validates_length_of :description, :maximum => 1000

include CommonScopes
end

Please refer this article for knowing the difference between include vs extend