如何在jenssegers / laravel-mongodb中放松？

I am using mongodb with Laravel. I also using jenssegers/laravel-mongodb for performing database activity. I have one collection containing data of the user where the path of his picture is stored with the tags given by him. Somewhat similar to Instagram. Now I want to perform tag wise count on the data i.e. for every tag, how many records are there. Below is the structure of the collection named user_contents:

{
    "_id": ObjectId("5a6f41fbf4f1f331b4006d7d"),
    "user_id": "1",
    "file_name": "rBrnbxjJXckR1CnvljZ4eZiXFWFWBobJiguUbHzd.jpeg",
    "tags": ["blue", "girl"],
    "created_at": ISODate("2018-01-29T15:47:06Z"),
    "updated_at": ISODate("2018-01-29T15:47:06Z")
}

I am runnig the below query to get the desired data which works perfectly in a mongo client

db.user_contents.aggregate([{
"$project": {
    "tags": 1
}
}, {
"$unwind": "$tags"
}, {
"$group": {
    "_id": "$tags",
    "count": {
        "$sum": 1
    }
}
}]);

But I don't know how to write this query using jenssegers. More specifically, I am not getting an option to execute unwind. It would be great if someone can help me with this,

Version info:

Laravel: 5.5.32

MongoDB: db version v3.6.2

php: 7.1.10

Thank you.

This is typically how I go about it:

User::raw(function ($collection) {
        return $collection->aggregate([
           ['$project' => [
                "tags" => 1,
                 ...
            ]],
            ['$unwind' => '$tags'],
            ['$group' =>
                [
                    '_id'=>'$tags',
                    'count' => ['$sum'=>1]
                ]
            ],
        ]);
    })