doc: easy docker command to run tests

README.md

@@ -129,6 +129,21 @@ Network Protocol
 
 Well, this is pretty "protocol-less", in the sense that when forwarding to a tcp address it will just open the connection and output raw traffic in the same way [netcat](http://en.wikipedia.org/wiki/Netcat) does.
 
+Run Tests
+---------
+
+The easiest way to run the tests is using docker:
+```shell
+docker run --rm -it $(docker build -q .)
+```
+
+To help debug, you can also make the test intermediary persistent by setting a volume for /tmp dir:
+```shell
+mkdir tmp
+docker run --rm -it -v $(pwd)/tmp:/tmp $(docker build -q .)
+```
+
+that will leave the intermediary files in the `tmp` folder.
 
 License
 -------