title: Mongodb findOne with or
body: <p>In my example i have a login view email or username can send one of two.</p>
  
  <pre><code>User.findOne({ 'email' :  email }, function(err, user) {
  // awesome user
  });
  </code></pre>
  
  <p>and i need something like this:</p>
  
  <pre><code>User.findOne({ 'email' :  email } || {'username' :  email}, function(err, user) {
  // awesome user
  });
  </code></pre>