title: Ember - computed sort
body: <p>I am using the below code for sorting a list.</p>
  
  <pre><code>sortOptions: ['amount:desc','place']
  Ember.computed.sort('model',sortOptions)
  </code></pre>
  
  <p>The key "amount" is basically a number, but in JSON "model", its coming as a string. So, when I ran this code, it wasn't sorting by amount, but when I modified the JSON to convert that amount string to amount number, that worked. 
  Is this correct behavior of Ember computed sort?</p>