set require.config path of `jquery` to `zepto` when use backbone-amd

zepto.js

/**
 * extend/zepto.js
 */

define([
  'zepto'
], function() {

  "use strict";

  window.Zepto = Zepto
  // If `$` or `jQuery` is not yet defined, point them to `Zepto`
  '$' in window || (window.$ = Zepto)
  'jQuery' in window || (window.jQuery = Zepto)

  return Zepto;

});

// Then set jquery path to extend/zepto:
require.config({
  paths: {
    'zepto': 'path/to/original/zepto',
    'jquery': 'extend/zepto'
  }
})