Adding new Postgres DB

[KonuTech]

Hello Friends
Can someone elaborate on how to add another Postgres DB using this Docker? I have been trying without success.
I am really admiring how easy it is to install a cluster ready to play with.
Would be awesome to use a DB dedicated strictly to my self-studying project instead of sharing it with Airflow. Thanks in advance.

IMO below does not works:

PostgreSql - Database Test:

Server: localhost:5432
Database: test
User: test
Password: postgres

I have been playing around with docker/docker-airflow files to make it work.