run as non-root

[rdmueller]

currently, the docker image creates files with root permissions.
It would be better if it would create files with the owner of the host system user.
It seems that you can run the image with the host system user by specifying -u $(id -u ${USER}):$(id -g ${USER}) but this user has problems with files within the container since these where created by root.

[rdmueller]

see also #10

[rdmueller]

should be fixed by now: https://github.com/docToolchain/docker-image/blob/ng-beta/alpine/Dockerfile