Readme changes including the change requested in issue #4 "Need to change image name from redsocks to munkyboy/redsocks in docker run command"

README.md

@@ -1,17 +1,46 @@
 A redsocks container primarily used to transparently utilize http(s) proxies.
 
-Inspired by https://github.com/jpetazzo/squid-in-a-can and
-https://github.com/wtsi-hgi/docker-proxify
+Fork of [munkyboy's docker-redsocks repository](https://github.com/munkyboy/docker-redsocks) in order to improve the documentation (at least, I will try).
+
+Inspired by [https://github.com/jpetazzo/squid-in-a-can](https://github.com/jpetazzo/squid-in-a-can) and
+[https://github.com/wtsi-hgi/docker-proxify](https://github.com/wtsi-hgi/docker-proxify).
 
 This container requires that you link the host network stack to the container.
 After starting the container, you will then issue iptable commands to redirect
-specific ports to the redsocks daemon.
+specific ports 80 and 443 to the redsocks daemon (see below).
+
+### Start Container
+
+#### Simple Example for HTTP Proxy only
+Change `http://yourproxy_IP_address_or_name:8080` by the IP address or name and TCP port that fits to your environment:
+```
+docker run --net=host -e http_proxy=http://yourproxy_IP_address_or_name:8080 munkyboy/redsocks
+```
+#### Example with HTTP proxy and HTTPS Proxy pointing to the same proxy URL
+Change `http://yourproxy_IP_address_or_name:8080` by the IP address or name and TCP port that fits to your environment:
+```
+export my_proxy=http://yourproxy_IP_address_or_name:8080
+docker run --net=host -e http_proxy=$my_proxy -e https_proxy=$my_proxy munkyboy/redsocks
+unset my_proxy
+```
 
-to run:
+#### Redirection on the Docker Host
+Upon starting, the start script will echo sample `iptables` commands that need to be issued on the Docker host, e.g. 
 ```
-docker run --net=host -e http_proxy=http://1.2.3.4:3128 redsocks
+iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to 12345
+iptables -t nat -A PREROUTING -p tcp --dport 443 -j REDIRECT --to 12346
 ```
+After you stop the container, you will need to cleanup the iptables rules again:
+```
+iptables -t nat -D PREROUTING -p tcp --dport 80 -j REDIRECT --to 12345
+iptables -t nat -D PREROUTING -p tcp --dport 443 -j REDIRECT --to 12346
+```
+
+#### Caveats
+The container is sharing the Docker host's network and is listening to port `12345` and `12346`. If one of those ports is already in use, you will not be able to start the container. In a HTTP-only case, you may use a port mapping like
+```
+docker run -p 54321:12345 ...
+```
+instead of `docker run --net=host ...`. However, this is not possible in case of HTTPS, since the container needs to share the network IP address of the host, if you do not want to get an SSL error (`403 Forbidden`).
+
 
-The container currently interprets the environment variables `http_proxy` and
-`https_proxy` to configure redsocks. Upon starting, the start script will echo
-sample `iptables` commands to issue on the host.