I have successsfully gotten a token mapper to connect to a database based on this

But the quarkus properties in conf/quarkus.properties don't seem to work at all.

I have also tried using ${env.SOME_VAR} in persistence.xml with it being passed in using an environment variable for persistence.xml In addition, I have tried to supply things like the following in the container setup without success. It just says it can't connect to the database at the url

-e JAVA_OPTS_APPEND="-Djavax.persistence.jdbc.url=jdbc:postgresql://user-details-d:5432/users_deets"  and 
-e SOME_VAR=jdbc:postgresql://user-details-d:5432/users_deets

Has anyone found an easy solution to this?
I'm researching creating an em programmatically. It seems a little involved. Or this leads me to believe that

Has anyone found an easier way to create their own with env variables or a similar mechanism that can be easily implemented?