Store User Data
When outsourcing user authentication, there is usually no need to maintain your own users/passwords table. Even so, you may still want to associate application data to authenticated users.
For example, you could have a Users table that lists each user authenticated by Auth0. Every time a users logs in, you could search the table for that user. If the user does not exist, you would create a new record. If they do exist, you would update all fields, essentially keeping a local copy of all user data.
Alternatively, you could store the user identifier in each table/collection that has user-associated data. This is a simpler implementation suited to smaller applications.