Trying to populate an array of ObjectID's within my schema. I've looked around at similar answers but it seems everyone is doing it slightly differently and I haven't been able to find a solution myself.

My schema looks like this:

```
var GameSchema = new Schema({
  title: String,
  description: String,
  location: String,
  created_on: { type: Date, default: Date.now },
  active: { type: Boolean, default: true },
  accepting_players: { type: Boolean, default: true },
  players: [{
    type: Schema.Types.ObjectId,
    ref: 'User'
  }],
  admins: [{
    type: Schema.Types.ObjectId,
    ref: 'User'
  }]
});

```

So far I've been trying to populate it like this, which obviously isn't working

```
exports.getAdmins = function(req, res) {
  Game.findById(req.params.id)
  .populate('admins')
  .exec(function(err, game) {
    return res.json(200, game.admins);
  });
};

```

I hate to add to the list of population questions, but I've looked at many and haven't found a solution. Any help is greatly appreciated!

Edit:
Here's how I am adding admins to the document

```
// Add admin to game
exports.addAdmin = function(req, res) {
  Game.findByIdAndUpdate(
    req.params.id,
    { $push: { 'admins': req.params.user_id }},
    function(err, game) {
      if(err) { return handleError(res, err); }
      if(!game) { return res.send(404); }
      return res.json(200, game.admins);
    });
};

```