title: Order by nested JSON field in Django admin
body: <p>I've got model User with <code>meta</code> field, which stores JSON data:</p>
  
  <pre><code>{
      "info": {
          "f_name": "John".
          "l_name": "Doe",
          "nick": "foo",
          ...
      },
      ...
  }
  </code></pre>
  
  <p>How can I specify ordering in Django admin by <code>meta['info']['l_name']</code>?</p>
  
  <p>I've tried:</p>
  
  <ol>
  <li><code>ordering = ( 'meta__info__l_name' )</code></li>
  <li><code>ordering = ( 'meta -&gt; info -&gt;&gt; l_name' )</code></li>
  <li><code>ordering ( RawSQL("main_user.meta -&gt; 'info' -&gt;&gt; 'l_name'", [], ), )</code></li>
  </ol>
  
  <p>Also, <code>user.id DESC</code> sorting is applied by default, which also breaks the desired behaviour.</p>
  
  <p>Django 2.1.2.</p>
  
  <p>Thank you in advance.</p>