Populate nested collections with Sails Js and async

Question

Im trying to query a deep association using sails js. In my example i have a one to many association between room and users and also a one to many association between user and pictures. My concern is if this is the correct way to assign pictures to users and also how can i map each collection of pictures to the corresponding user. Thanks.

// RoomController

show: function(req, res) {

    async.auto({

      room: function(cb) {
        var slug = req.param('slug');

        Room
          .findOneBySlug(slug)
          .populate('users', { where: { is_active: true, is_online: true } })
          .populate('messages', { limit: 30, sort: 'createdAt DESC' })
              .exec(cb)
      },

      pictures: ['room', function(cb, results) {
        if (!results.room) return res.badRequest('User not found.');

        Picture
          .find({user: _.pluck(results.room.users, 'id')})
          .where({'is_primary': true})
          .exec(cb);
      }],

      map: ['pictures', function(cb, results) {
        var room = results.room.toJSON();

        room.users = room.users.map(function(user) {
          user.pictures = results.pictures;
          return user;
        });
        return cb(null, room);
      }]

  },

     function finish(error, results) {
       if (error) return res.serverError(error);

       console.log(results.map)
     }

  );

}