Two applications same database

Hello fellow programmers,
I have built a first application using devise and postgresql to sign up the admin for the exercise. The first application is for sign up purpose only.

https://github.com/AsimKhan2019/RORDBApp1

I want to use the same admin model and the postgresql database from the first application and use it in the second application to login the admin into the portal, and not sign up.

https://github.com/AsimKhan2019/RORDBApp2

Is there a way for me to achieve that?