title: How to group by date regardless of time?
body: <p>I'm trying to group by Date(). I've got 3 records with the <code>created_at</code> column: </p>
  
  <pre><code>2011-12-03 08:00:24, 2011-12-03 08:12:10, 2011-12-04 09:00:00
  </code></pre>
  
  <p>I'd like to only group by year, month and day, regardless of time. So for the example above. It should only return two rows: </p>
  
  <pre><code>2011-12-03 and 2011-12-04
  </code></pre>
  
  <p>How should I go about this?</p>