This is a Docker image containing nginx which has been modified to support Shibboleth by David Beitey.
Grab it from Docker:
docker pull iohannesarnold/nginx-shibboleth
To control the nginx configuration, first create a nginx config directory somewhere on your system; if you don't have one in mind, you can use the default from this package:
curl -O https://raw.githubusercontent.com/IohannesArnold/nginx-shibboleth/master/nginx
docker run -d -p 80:80 -v /host/nginx/dir:/etc/nginx:ro iohannesarnold/nginx-shibboleth
You can then configure your nginx setup by follow Beitey's post above. Restart your nginx container by running:
docker restart CONTAINER_ID_OR_NAME