Mongoose Schema

gistfile1.js

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'
  }]
});

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

^ Schema and the getAdmins function aren't in the same file FYI, just shown here for simplicity