title: Order by split string django orm
body: <p>I have an ID as a reference number and year in this format:</p>
  
  <pre><code>1/17
  98/15
  2/17
  112/17
  2345/17
  67/17
  9/17
  8974/16
  </code></pre>
  
  <p>When i get my IDs out using django orm:</p>
  
  <pre><code>obj = MyIDs.objects.filter(run='run_1').order_by('ID')
  </code></pre>
  
  <p>I get them out in the order of the first number:</p>
  
  <pre><code>1/17
  112/17
  2/17
  2345/17
  67/17
  8974/16
  9/17
  98/15
  </code></pre>
  
  <p>However as the number after the / is the year, I would like to order them by the year then number. I am able to do this easily in mySQL (using substring index etc) and also if it was a python list, but as I am now wanting to not process my objects before sending them to my html template - is there a way to do this in the orm?</p>