Fixed bug: ObjectManager attributes are added twice when running all migrations and seeds.

db/migrate/20160217000001_object_manager_update_user.rb

@@ -1,5 +1,9 @@
 class ObjectManagerUpdateUser < ActiveRecord::Migration
   def up
+
+    # return if it's a new setup
+    return if !Setting.find_by(name: 'system_init_done')
+
     UserInfo.current_user_id = 1
     ObjectManager::Attribute.add(
       force: true,