title: How to properly set up the Backbone.js urlRoot method
body: <p>I am having trouble understanding how <code>urlRoot</code> works in Backbone.js. I am attempting to fetch a task with a specific <code>_id</code> from a NodeJS/MongoDB backend.</p>
  
  <p>What I'm not exactly clear on is how to pass the id attribute into the URI. I've been doing the following from Chrome dev tools:</p>
  
  <pre><code>var task = new App.Models.Task({ id: '51c09ae7d3b35d29d4dfdecd' });
  task.fetch();
  </code></pre>
  
  <p>And I receive the following error:</p>
  
  <pre><code>GET http://localhost:3000/tasks/:_id 500 (Internal Server Error) 
  </code></pre>
  
  <p>How do I properly set this up?</p>
  
  <p>Here's my Backbone code:</p>
  
  <pre><code>(function() {
  
    window.App = {
      Models: {},
      Views: {},
      Collections: {}
    };
  
    App.Models.Task = Backbone.Model.extend({
      defaults: {
        title: '',
        completed: false
      },
  
      idAttribute: "_id",
  
      urlRoot: '/tasks/:_id'
    });
  
  })();
  </code></pre>