title: backbone.js use different urls for model save and fetch
body: <p>My back-end has two separate pages, one for handling the model save request and the other for model fetch. </p>
  
  <p>What is the best approach for calling save() and fetch() to use different URLs? Thanks.</p>
  
  <p><strong>Edit:</strong>
  After studying the annotated source, I see that one can actually supply an <code>options</code> hash to <a href="http://documentcloud.github.com/backbone/docs/backbone.html#section-40">fetch</a> and <a href="http://documentcloud.github.com/backbone/docs/backbone.html#section-41">save</a></p>
  
  <pre class="lang-js prettyprint-override"><code>//taken from backbone source:
  save : function(attrs, options) {
    options || (options = {});
    if (attrs &amp;&amp; !this.set(attrs, options)) return false;
    var model = this;
    var success = options.success;
    options.success = function(resp, status, xhr) {
      if (!model.set(model.parse(resp, xhr), options)) return false;
      if (success) success(model, resp, xhr);
    };
    options.error = wrapError(options.error, model, options);
    var method = this.isNew() ? 'create' : 'update';
    return (this.sync || Backbone.sync).call(this, method, this, options);
  },
  </code></pre>
  
  <p>In the save, what purpose does the <code>attrs</code> serve? I've just been calling myModel.save() without passing anything in and it's always been hashing my model's attributes correctly. But now that I want to supply a 'save url' and I'm tempted to call</p>
  
  <pre><code>myModel.save(undefined, {
      url: 'myPath'
  })
  </code></pre>
  
  <p>with the undefined required to 'skip' the first <code>attrs</code> paramter.</p>