mixin_include.rb

module Utilities
 def self.included(base)
   base.extend(ClassMethods)
 end

  def method_one
    puts 'Hello from an instance method'
  end

  module ClassMethods
    def method_two
      puts 'Hello from a class method'
    end
  end
end

class Example
  include Utilities
end

Example.new.method_one
Example.method_two