Using Custom VSS Data Entries - Missing volume mapping in the user_guide.md

[PySchilling]

The user_guide.md give the following example for loading a custom specification file in the chapter Using Custom VSS Data Entries.

docker run --rm -it -p 55555:55555 ghcr.io/eclipse-kuksa/kuksa-databroker:main --insecure --vss vss.json

See: https://github.com/eclipse-kuksa/kuksa-databroker/blob/main/doc/user_guide.md#using-custom-vss-data-entries

This results in the following error message:

Error: Os { code: 2, kind: NotFound, message: "No such file or directory" }

The solution would be to map the file into the docker container.

docker run --rm -it -p 55555:55555 -v ./vss.json:/vss.json ghcr.io/eclipse-kuksa/kuksa-databroker:main --insecure --vss vss.json

Maybe this should be added to the documentation.

[lukasmittag]

If you would be so kind and create a PR for this we would appreciate it :)