post histories finished

app/models/post_history.rb

@@ -51,9 +51,13 @@ class PostHistory < ActiveRecord::Base
       hash["updated_at"]
     end
     
-    def updater_id
+    def user_id
       hash["user_id"]
     end
+
+    def presenter
+      @presenter ||= PostHistoryRevisionPresenter.new(self)
+    end
   end
 
   before_validation :initialize_revisions, :on => :create