title: mongo search for part of string match in words array
body: <p>I want to find partial string matching in mongodb list element
  for example my search string is:</p>
  
  <p><em>"Hello world we are on mars"</em></p>
  
  <p>my records tags are:</p>
  
  <ol>
  <li><em>words : ["hell", "bubu world"]</em></li>
  <li><em>words : ["<strong>we are</strong>", "cookie"]</em></li>
  <li><em>words : ["are nono mars", "w"]</em></li>
  </ol>
  
  <p>I want to get bask only record number 2 where <strong>one</strong> of the array elements is matched</p>