gistfile1.js

// load this in admin.js
Tenement.Model = Backbone.Model.extend({
  url: function () {
    return '/admin/api' + this.urlRoot; 
  }
});

// load this one in application.js
Tenement.Model = Backbone.Model.extend({
  url: function () {
    return '/app/api' + this.urlRoot; 
  }
});

// Tenement.Model will be different file
Tenement.Models.Room = Tenement.Model.extend({
    paramRoot: 'room',

    urlRoot: '/rooms',

    toString: function() {
        return this.get('name');
    }
});