title: $gte and $lte in mongoose with multiple condition
body: <p>Am I using <code>$gte</code> and <code>$lte</code> wrongly with other condition? I got empty array, but when I do just <code>user_email:req.bodu.user_email</code> I'm able to get all the data.</p>
  
  <pre><code>function firstDayOfMonth() {
    var d = new Date(Date.apply(null, arguments));
    d.setDate(1);
    return d.toISOString();
  }
  
  function tomorrowDate() {
    var d = new Date();
    d.setDate(d.getDate() + 1)
    return d.toISOString();
  }
  
  Users.find({
      "user_email": req.body.user_email,
      "createdAt": {
        "$gte": firstDayOfMonth(),
        "$lte": tomorrowDate()
      }
    },
    function(err, response) {
      if (!err) {
        console.log(response)
        res.json(response);
      }
    });
  </code></pre>