I had to make several adjustments to make it work with nixos:
* Replace relative config file lookups with ENV variable.
* Modify gitlab-shell to not clear then environment when running
pre-receive.
* Modify gitlab-shell to write some environment variables into
the .authorized_keys file to make sure gitlab-shell reads the
correct config file.
* Log unicorn output to syslog.
I tried various ways of adding a syslog package but the bundler would
not pick them up. Please fix in a better way if possible.
* Gitlab-runner program wrapper.
This is useful to run e.g. backups etc. with the correct
environment set up.
