Documentation for Beginners

When building a _testnet_ Docker stack of Dogeparty containers, absolute beginners will probably fall short on the intricacies of combining the two technologies.

Therefore I propose complemetary documentation about Docker, only to be present in the context of dogecoind-docker/testnet.

As for http://www.inkpad.io/1GMXYwxl4Q, I propose the following

\-    ...Try a testnet installation for each component before going into production.
\+    ...Try a testnet installation (starting at https://github.com/Dogeparty/dogecoind-docker/tree/master/testnet) for each component before going into production.