NGINX image for OpenShift

based on the official nginx image with the following modifications to be able to run on openshift:

• listens on port 8081
• directories /var/cache/nginx, /var/run and /var/log/nginx are writeable for root group
• removes the user directive from /etc/nginx/nginx.conf

More details about this repository and why the modifications are necessary to run nginx on OpenShift can be found in this blog https://torstenwalter.de/openshift/nginx/2017/08/04/nginx-on-openshift.html.