title: Backbone.js set URL parameters in model & use it with fetch
body: <p>I would like to fetch model from specific url with parameter:
  url: server/somecontroller/id/?type=gift</p>
  
  <p>Simple working way is:</p>
  
  <pre><code>collection.fetch({ data: { type: 'gift'} });
  </code></pre>
  
  <p>But I want to set it in model:</p>
  
  <pre><code>    ...
      if(id){
        App.coupon = new AffiliatesApp.Coupon({id: id});
      } else {
        App.coupon = new AffiliatesApp.Coupon({id: 'somecontroller'}, {type: 'gift'});
      }
      App.coupon.fetch();
  </code></pre>
  
  <p>How can I achieve it?</p>