title: sort strings like "2013/2014" in ng-repeat
body: <p>I'm trying to order items by one of their field which contains years written as such : <code>"2013/2014", "2017/2018", "2014/2015" etc....</code></p>
  
  <p>I would like them to be ordered like this : <code>"2017/2018", "2014/2015", "2013/2014".</code> This sounds super trivial but I can't figure out how to do it without converting everything to numbers, which I don't really want to do because of the "/".</p>
  
  <p>Any suggestions ? :)</p>