- User needs login rights
CREATE USER guacamole PASSWORD 'supersecret';
CREATE DATABASE guacamole owner guacamole;

- init database
docker run --rm guacamole/guacamole /opt/guacamole/bin/initdb.sh --postgres > initdb.sql
psql -U guacamole -d guacamole < initdb.sql

- set user rights
GRANT ALL ON ALL TABLES IN SCHEMA public TO guacamole;
GRANT ALL ON ALL SEQUENCES IN SCHEMA public TO guacamole;