code: function createAlias() {
    Ember.RouterDSL.prototype.alias = function(aliasRoute, aliasPath, aliasTarget) {
      Ember.assert('You must create a route prior to creating an alias.', this.handlers || this.intercepting);
      Ember.assert('The alias target must exist before attempting to alias it.', this.handlers[aliasTarget]);
  
      // Grab a reference to the arguments passed in for the original route.
      let [options, callback] = this.handlers[aliasTarget];
      options.path = aliasPath;
  
      this.intercepting.push({ aliasRoute, aliasTarget });
  
      this.route(aliasRoute, options, callback);
    };
  }
docs: Sets up our magic alias function.