customizing collection fetch http://stackoverflow.com/questions/18383205/backbone-js-with-a-custom-fetch-url

gistfile1.js

MyCollection = Backbone.Collection.extend({

  model:MyModel,

  url: "/mymodels",

  fetchPerCategory: function (categoryId, options) {

  options = options || {};

  if (options.url === undefined) {

    options.url = "/custom_mymodels/" + categoryId;

  }

    return Backbone.Model.prototype.fetch.call(this, options);

  }

});