Run instructions

README.md

@@ -21,4 +21,6 @@ List the `users` you'd like to include in the chat, separated by commas.
 
 ### Usage
 
+`> python3 main.py`
+
 Each user gets their own input line at the bottom of the window. Pressing `Enter` in a given input line will send that line (and *only* that line, not any of the others) to the chat window. Easy as that!