[{"_id":{"$oid":"62812fac06f29f5fe874c0db"},"model":"fire","allRatings":[{"user_id":"6282962e3aa8163084776092","rating":9},{"user_id":"62811d520f52b64990a94e99","rating":6}],}]

db.collection.aggregate([{$match:{_id:ObjectId("62812fac06f29f5fe874c0db")}},{$project:{model:1,hasRated:{"$in":["6282962e3aa8163084776092","$allRatings.user_id"]}}}])