title: MongoDB working with multiple connections
body: <p>When I use mongoose.connection, models are connected directly with the unique connection.
  In this case db1 is only used for quering (not model require). But db2 use  2 models.
  ¿How Can I connect those models with db2 only?</p>
  <p>Thanks for helping</p>
  <pre><code>const db1 = mongoose.createConnection(&quot;atlasuri&quot;).asPromise()
  const db2 = mongoose.createConnection(&quot;localuri&quot;).asPromise()
  
  app.get(&quot;/&quot;,async(req,res)=&gt;{
      const finded =  (await db1).collection(&quot;users&quot;)
      await finded.forEach(el=&gt; console.log(el))
      res.json(finded)
  })
  </code></pre>
  <p>Models</p>
  <pre><code>const Criterion1=new mongoose.model('Criterion',new mongoose.Schema({
   name:string
  }));
  const User=new mongoose.model('Criterion',new mongoose.Schema({
   name:string
  }));
  </code></pre>