title: Issue with getJSON within Backbone view rendering
body: <p>I'm pretty new to Backbone.js, loving it so far, but I'm having a little trouble trying to get relational data to render.</p>
  
  <p>Within my Backbone view (called ImagesView) I have the following code:</p>
  
  <pre><code>// Render it
  render: function () {
  
    var self = this;
  
    // Empty the container first
    self.$el.html("")
  
    // Loop through images
    self.collection.each(function(img){
  
      // convert `img` to a JSON object
      img = img.toJSON()
  
      // Append each one
      self.$el.append(self.template(img))
  
    }, self)
  }
  </code></pre>
  
  <p>There are 3 images in the collection, and they are templated correctly with the above code. Within the <code>img</code> object is a <code>user</code> attribute, containing the User ID. I'm trying to return the user's details, and use these within the template instead of the ID. I'm doing that using the code below:</p>
  
  <pre><code>// Render it
  render: function () {
  
    var self = this;
  
    // Empty the container first
    self.$el.html("")
  
    // Loop through images
    self.collection.each(function(img){
  
      // convert `img` to a JSON object
      img = img.toJSON()
  
      /* New code START */
  
      // Each img has a `user` attribute containing the userID
      // We'll use this to get their details
      $.getJSON('/user/' + img.user, {}, function(json, textStatus) {
        img.photographer = {
          id: json.id,
          username: json.username,
          real_name: json.real_name
        }
  
        /* Moved 1 level deeper */
        // Append each one
        self.$el.append(self.template(img))
      });
  
      /* New code END */
  
    }, self)
  }
  </code></pre>
  
  <p>When I do this, the user's details are returned correctly and inserted into the template, but I now get 3 of each image returned instead of 1 (i.e. 9 in total), in a completely random order. What am I doing wrong? I'm open to using Backbone methods instead of the getJSON if that will make it easier, I just couldn't get it to work myself. I'm using underscore.js for the templating</p>