update readme, add small documentation

Author: sopitz

README.md

@@ -1,4 +1,16 @@
 # letsencrypt-nginx-proxy
-reverse proxy with automated vHost and SSL-cert generation
+letsencrypt-nginx-proxy is based on [jwilder/nginx-proxy](https://github.com/jwilder/nginx-proxy/). It sets up a container running nginx and [docker-gen](https://github.com/jwilder/docker-gen).
+See [Automated Nginx Reverse Proxy for Docker](http://jasonwilder.com/blog/2014/03/25/automated-nginx-reverse-proxy-for-docker/) for why you might want to use this.
+In addition tothe functionality that [jwilder/nginx-proxy](https://github.com/jwilder/nginx-proxy/ ) offers (reverse proxy configs for nginx and reloads nginx when containers are started and stopped) we use with docker-gen to generate a SSL certificate from letsencrypt to secure the domain.
 
-- todo: add detailed description
+### Usage
+If you want to run it without SSL support, please have a look at the page for the  [jwilder/nginx-proxy](https://github.com/jwilder/nginx-proxy/). That's what you're actually looking for.
+
+To run it:
+
+    $ docker-compose up -d
+
+That's about it already.
+
+### Configuration
+If there's anything else you want to configure. Please also have a look at [jwilder/nginx-proxy](https://github.com/jwilder/nginx-proxy/). There you'll find more beautiful documentation on how to do more magic with this reverse proxy.