title: "Order by"  result of  "group by" count?
body: <p>This query </p>
  
  <pre><code>Message.where("message_type = ?", "incoming").group("sender_number").count
  </code></pre>
  
  <p>will return me an hash.</p>
  
  <pre><code>OrderedHash {"1234"=&gt;21, "2345"=&gt;11, "3456"=&gt;63, "4568"=&gt;100}
  </code></pre>
  
  <p>Now I want to order by count of each group. How can I do that within the query.</p>