{
    "rules": {
        ".read": true,
        "$user": {
            ".write": "auth.id !== null"
        }
    }
}

{
    "rules": {
        ".read": true,
        "$user": {
            ".write": "auth.id !== $user"
        }
    }
}

Enforce users to write in their own location.
Enforce users to write in their own location.
