title: How to keep image at the back of the canvas when moving elements with fabric.js?
body: <p>I have a large image loaded initially into my canvas, and then I would like to be able to draw rectangles over it. When I drag the image around, I still want the rectangles to appear over the image, instead of them being pushed to the back.</p>
  
  <p>Here is a plunk;</p>
  
  <p><a href="http://plnkr.co/edit/iJV0bZrlCG4CJXlhDw8w?p=preview" rel="noreferrer">http://plnkr.co/edit/iJV0bZrlCG4CJXlhDw8w?p=preview</a></p>
  
  <p>If possible, I would like to be able to ensure that no matter what, the image is always at the back? I've looked around quite extensivley, and cannot find a solution. It is becoming increasingly frustrating!</p>
  
  <p>Initially I thought it would be as simple as this;</p>
  
  <pre><code>canvas.on('object:moving', function(e) {
  
    var obj = e.target;
    console.log(obj.id)
    if (obj.id === 'img') {
      canvas.sendToBack(obj)
    } else {
      canvas.bringToFront(obj)
    }
  
  
  });
  </code></pre>
  
  <p>Hope someone can help!</p>