[keycloak-user] initialising docker

I've been struggling with a clean way to initialize the keycloak docker container. I need to import a realm definition, and the only way I can find is it start the image with the import options, wait for this to complete so that the database is populated and then to Ctrl-C out and to restart the container proper, which is hardly automatable. With 1.8 this also needs to include defining the admin user. Is there a cleaner way of achieving this? For instance, with the postgres docker images you just put any initialisation *.sql or *.sh scripts in a specific directory and they get executed first time the server starts. Tim