Object Auth. Now object can be included with "include OrbitCoreLib::ObjectAuthable" to use kernel method,such as

1.Object.authed_for_user(user,title_of_object_auth).  title_of_object_auth is optional
2.object.authed_users(user,title_of_object_auth) .  title_of_object_auth is optional
if title_of_object_auth is not given,then it will return calculation across all possiblity.

vendor/built_in_modules/new_blog/app/models/post.rb

@@ -1,9 +1,10 @@
 class Post
   include Mongoid::Document
   include Mongoid::Timestamps
+  include OrbitCoreLib::ObjectAuthable
+  
   field :title, :type => String
   field :body, :type => String
   embeds_many :comments
   validates_presence_of :title, :body
-  has_one :object_auth,as: :obj_authable,dependent: :delete
 end