title: datetime UTC conversion in mongodb
body: <p>I do <code>new Date()</code> then save it into mongodb, the date became UTC format? </p>
  
  <p>The datetime I inserted into mongodb when pull back is not the same, what should I do to solve this? Like I create a document on 1/12/2016, and I select range from 1/12/2016, the record is not there. Strange.</p>