add a quick example to show how to use it.

README.md

@@ -5,6 +5,34 @@ The ntunnel program is designed to tunnel Unix domain sockets over TCP,
 using the [Noise Protocol](https://noiseprotocol.org/).  The goal is to
 be secure and simple to use and setup.
 
+Example
+-------
+
+Generate the keys:
+```
+python ntunnel.py genkey serverkey
+python ntunnel.py genkey clientkey
+```
+
+Create the target for the pass through:
+```
+nc -lU finalsock
+```
+
+Start the server and client:
+```
+python ntunnel.py server serverkey unix:$(pwd)/servsock unix:$(pwd)/finalsock
+python ntunnel.py client clientkey serverkey.pub unix:$(pwd)/clientsock unix:$(pwd)/servsock
+```
+
+Attach to the client:
+```
+nc -U clientsock
+```
+
+Now when you type text into either of the nc windows, you should see
+the same text come out the other side.
+
 Running Tests
 -------------