Docker build failing

[gardenrobot]

I noticed the docker build was failing, I suspect from this change. It seems COPY --chown requires a group when given a username. I've written a PR that sets it to nogroup.

docker build -t tmp -f Dockerfile .

Step 9/14 : COPY --chown=radicale --from=builder /app/venv /app
ERROR: Service 'radicale' failed to build: unable to convert uid/gid chown string to host mapping: can't find gid for group radicale: no such group: radicale

#1420

[pbiering]

would it be not better to create the group radicale in advance and specify it then with using --gid radicale

 adduser radicale --home /var/lib/radicale --system --uid 1000 --disabled-password

[gardenrobot]

yeah, that'd be closer to a non-docker environment. updated