title: Sort queryset by values in list
body: <p>Is it possible to sort a django queryset by the list of elements provided in the query?
  For example, if I do </p>
  
  <pre><code>m.objects.filter(id__in=[3,1,8])
  </code></pre>
  
  <p>I wan't the order of the queryset to be the element of id 3, the element of id 1 and the element of id 8.</p>
  
  <p>Thanks</p>