keystone.list('Blurt').model.aggregate([
    {
        $lookup:{
            from: "users",
            localField: "author.id",
            foreignField: "_id",
            as: "userImg"
        }
    }
    ,
    {
        $unwind: '$userImg'
    },
    {
        $match: { 'author.id': {$ne: req.user._id}}
    },
    {
        $sample: {'size': 3}
    },
    {
        $project: {
            _id: '$userImg._id',
            name: '$userImg.name',
            smImg: '$userImg.smImg',
            text: 1,
            vote: 1,
            blurtDate: 1,
            blurtImg: 1
        }
    }
    ]).sort({ blurtDate: -1 })
    .cursor().exec()
    .toArray(function(err, data) {
        console.log(data);
        res.json(data);
    });