Handling Users with MongoDB Stitch App within Atlas Cluster

I have an MongoDB Stitch app, that users the Email/Password authentication. This creates users within the Stitch App that I can authenticate on the page. I also have an MongoDB Atlas Cluster for my database. In the cluster I have a DB with the name of the project, then a collection underneath that for 'Matches'. So when I insert the 'Matches' into the collection, I can send the authenticated user id from Stitch, so that I have a way to query all Matches for a particular User. But how can I add additional values to the 'User' collection in stitch? That user section is sort of prepackaged in Stitch with whatever authentication type you choose (email/password). But for my app I want to be able to store something like a 'MatchesWon' or 'GamePreference' field on the 'User' collection.

Should I create a collection for 'Users' the same way I did for 'Matches' in my Cluster and just insert the user id that is supplied from Stitch and handle the fields in that collection? Seems like I would be duplicating the User data, but I'm not sure I understand another way to do it. Still learning, I appreciate any feedback/advice.

There isn't currently a way to store your own data on the internal user objects. Instead, you can use authentication triggers to manage users. The following snippet is taken from these docs.

exports = function(authEvent){
   // Only run if this event is for a newly created user.
   if (authEvent.operationType !== "CREATE") { return }

   // Get the internal `user` document
   const { user } = authEvent;

   const users = context.services.get("mongodb-atlas")
       .db("myApplication")
       .collection("users");

   const isLinkedUser = user.identities.length > 1;

   if (isLinkedUser) {
        const { identities } = user;
        return users.updateOne(
            { id: user.id },
            { $set: { identities } }
        )

    } else {
        return users.insertOne({ _id: user.id, ...user })
             .catch(console.error)
    }
};