I'm trying to use CASL for authorization check of nested items.
It uses mongoose for query data and check access.

My domain is that:

* A "User" could has more "Vehicles"
* A "Document" must have a Vehicle

Schema:

```
vehicle { users: [ {type: objectId, ref: 'user'} ] }
document { vehicle: {type: objectId, ref: 'vehicle' }}

```

To find the vehicle "by user" I do:

```
db.getCollection('vehicle').find(
    { users: {$in: [ ObjectId("5ae1a957d67500018efa2c9d") ]} }
)

```

That works.

In the documents collection, the data has records such as this:

```
{
    "_id": ObjectId("5aeaad1277e8a6009842564d"),
    "vehicle": ObjectId("5aea338b82d8170096b52ce9"),
    "company": "Allianz",
    "price": 500,
    "date_start": ISODate("2018-05-02T22:00:00.000Z"),
    "date_end": ISODate("2019-05-02T22:00:00.000Z"),
    "createdAt": ISODate("2018-05-03T06:32:50.590Z"),
    "updatedAt": ISODate("2018-05-03T06:32:50.590Z"),
    "__v": 0
}

```

To find the document "by user" I do:

```
db.getCollection('document').find(
    { "vehicle.users": {$in: [ ObjectId("5ae1a957d67500018efa2c9d") ]} }
)

```

It doesn't work. Is possibile to do that in one single "find" query?