title: Inserting Object into Mongo with _id Output
body: <p>How can I insert a new object into Mongo and get the <code>_id</code> with the inserted document?</p>
  
  <p>Desired behavior:</p>
  
  <p><code>val _id: String = coll.insert(someObj)</code> // _id = "_id" of inserted doc</p>