I guess that aal image is a derivative from tryton/tryton. If so be sure that it is using the /entrypoint.sh which is responsible to set the environment variables.
You’re connecting to the default database postgres because you’re setting the -U (user) param to postgres. You do not provide the postgres database password anywhere - which is not the problem.
To target the aal database as defined in the step 1 on POSTGRES_DB, add the database name in the psql command.