title: Mongodb default with current timestamp on insert
body: <p>Is it possible to have a field with a default value as a current timestamp on insert? It's possible to do this with an update:</p>
  
  <pre><code>self.db.history.insert(activity, { '$current_date': { 'timestamp': { '$type': 'timestamp' } } })
  </code></pre>
  
  <p>But <a href="http://docs.mongodb.org/manual/reference/operator/update/currentDate/" rel="nofollow">$current_date</a> only works for update.</p>
  
  <p>Maybe I should just create a timestamp in Python since a few milliseconds or seconds won't be a problem.</p>