Auth0, Firebase integration, post-registration hook

As per title, I’ve found it quite challenging to understand how to weave Auth0 and Firebase together.

What I would like is simple (in theory):
My app only has social login, so database connections for username/password.

When a user first registers with my app, I would like to create an entry in firebase. This may be a rule/hook (preferably since rules are being phased out i believe).

How can I achieve this? I watched the video in the rules page but it is outdated as it was created 2 years ago,


:wave: @rainman are you having Firebase as your backend?