Build using docker-compose up.
PostgreSQL
Log in using docker exec -it itk-postgres psql -U robin -d itk once it's running. You can interactively run queries from here.
Grafana
Go to http://localhost:3000 to log-in. The username is admin and the password is password. You can add the postgres database created in the other container as you would another data source. Pass the database credentials from the docker-compose file and use itk-postgres:5432 as the host.
To rebuild everything from scratch and start again, you need to remove the containers and the volumes.