Run devpi as non-root user

[AmirHmZz]

It would be better to make images run as non-root user in order to increase their security.

[JonasAlfredsson]

Hi AmirHmZz,

This image is so simple you can probably just start it as another user, you just need to create the initial folder:

mkdir ./server
chown 1000:1000 ./server
docker run -it --rm -e DEVPI_PASSWORD=pass \
    -v ./server:/devpi/server --user 1000:1000 \
    jonasal/devpi-server

and you can change the IDs to whatever you want.