Refinery CMS: Uncaught TypeError: undefined is not a function - init_sortable_menu

I'm using gem 'refinerycms', '~> 2.0.0' ruby '2.2.3' and gem 'rails', '3.2.22'

But when i edit any page then i'm facing following issue. Can someone guide me what will be the issue?

Uncaught TypeError:

undefined is not a function

init_sortable_menu init_refinery_admin jQuery.Callbacks.fire

jQuery.Callbacks.self.fireWith refinery.js:436

jQuery.extend.readyrefinery.js:950 DOMContentLoaded