Consider normalized docker-compose files for testing.

[codefromthecrypt]

Keep a simple docker-compose for first-time users, but consider docker-compose{,-mysql}.yml using https://docs.docker.com/compose/extends/ for testing.

Maybe even go as far as having docker-compose-{common,mysql,cassandra}.yml. The trade-off in the latter case is of course that users will need to keep typing -f $FILE, which may or may not be an issue.