Own hosted openrouteservice instance not working

@LittleBoxOfChicken @SimonDahrs

If you could assist a little by trying if this PR resolves your issues, that’d be appreciated:

The image is not available on dockerhub yet, but you can pull the associated branch and do a manual build:

docker build -t openrouteservice/openrouteservice:test_docker --build-arg OSM_FILE=./your_osm.pbf APP_CONFIG=./your.app.config .

Or even omit the build-args and specify those as environment variables in the docker-compose.yml to launch a container.