title: Mongoose autoReconnect option
body: <p>I'm trying to set up the MongoDB auto reconnection feature via Mongoose. Every way that I have tried to pass the option has had no effect, or at least the <code>reconnected</code> event isn't being emitted.</p>
  
  <p>What I've tried:</p>
  
  <pre><code>mongoose.createConnection("mongodb://localhost:27017/test", { auto_reconnect: true });
  mongoose.createConnection("mongodb://localhost:27017/test", { autoReconnect: true });
  mongoose.createConnection("mongodb://localhost:27017/test", { server: { auto_reconnect: true } });
  mongoose.createConnection("mongodb://localhost:27017/test", { server: { autoReconnect: true } });
  </code></pre>
  
  <p>If one of these is correct, the <code>reconnected</code> event should be triggered and a message should be logged in the console, however this never happens.</p>
  
  <p>If there is a delay before the reconnection, does anyone know how to configure it?</p>
  
  <p>Thanks in advance</p>
  
  <p>For anyone looking into this, take a look at <a href="https://github.com/LearnBoost/mongoose/issues/1479">this</a> and <a href="https://github.com/LearnBoost/mongoose/issues/1672">this</a> issue in mongoose repository.</p>