100 containers

Various useful stuff in containers with docker-compose. Contents:

1. Crontab in an environment variable: a way to use cron in a container and not hate yourself.
2. Auth proxy for Docker registry: use private registry without docker login.
3. NGINX Print All Request Headers: set up a proxy to a real service and see what headers are coming through proxy.
4. NGINX Configuration Helper: experiment with NGINX configuration.

More to come later.