title: Group array after unwind and match
body: <p>I have a twice nested schema:</p>
  
  <pre><code>mongoose.model('Team', mongoose.Schema(
  {
   players : [{ 
      trikots : [{
          isNew : Boolean,
          color : String
      }]
   }]
  })
  </code></pre>
  
  <p>For now, my query looks like this:</p>
  
  <pre><code>Team.aggregate()
          .match({'_id' : new ObjectId(teamId)})
          .unwind('players')
          .unwind('players.trikots')
          .match({'players.trikots.isNew' : 'red', 'players.trikots.isNew' : true})
          .exec(sendBack);
  </code></pre>
  
  <p>But I would like to have one Team object, that contains all players as an array. How can I achieve that?</p>