title: How to group data in object?
body: <p>I am receiving data in this format:</p>
  
  <pre><code>{2013-09-13 22:55:56 UTC=&gt;1, 2013-09-15 13:14:19 UTC=&gt;1, 2013-09-16 13:05:39 UTC=&gt;1, 2013-09-16 19:12:44 UTC=&gt;1}
  </code></pre>
  
  <p>I would need to <code>group</code> them according to day, to this shape:</p>
  
  <pre><code>{2013-09-13=&gt;1, 2013-09-15=&gt;1, 2013-09-16=&gt;2}
  </code></pre>
  
  <p>How to do this in Ruby?</p>