adding getter and setter for saas in the scoped document

lib/saasable/mongoid/scoped_document.rb

@@ -1,26 +1,34 @@
 module Saasable::Mongoid::ScopedDocument
   @scoped_documents = []
-  
+
   def self.included klass
     @scoped_documents << klass unless @scoped_documents.include? klass
-    
+
     klass.extend ClassMethods
     klass.class_eval do
       field :saas_id, :type => BSON::ObjectId
     end
   end
-  
+
   def self.scoped_documents
     @scoped_documents
   end
-
+
+  def saas= a_saas
+    self.saas_id = a_saas._id
+  end
+
+  def saas
+    @saas ||= Saasable::Mongoid::SaasDocument.saas_document.find(self.saas_id)
+  end
+
   module ClassMethods
     def validates_uniqueness_of(*args)
       attributes = _merge_attributes(args)
       attributes[:scope] ||= []
       attributes[:scope] << :saas_id unless attributes[:scope].include?(:saas_id)
-      
+
       validates_with(Mongoid::Validations::UniquenessValidator, attributes)
     end
   end
-end
+end