title: php - can't convert date from string
body: <p>I want to get this date's timestamp from string. I'm trying:</p>
  
  <pre><code>DateTime::createFromFormat("Y-m-d", "2015-05-18T23:45:21.604Z");
  </code></pre>
  
  <p>But it returns nothing. I don't know which format is this.</p>