Add link to old code

README.md

@@ -3,18 +3,24 @@
 
 A Flappy Bird Clone made using [python-pygame][pygame]
 
+> If you are in interested in the old one-file code for the game, you can [find it here][one-file-game]
+
+[pygame]: http://www.pygame.org
+[one-file-game]: https://github.com/sourabhv/FlapPyBird/blob/038359dc6122f8d851e816ddb3e7d28229d585e5/flappy.py
+
+
 Setup (as tested on MacOS)
 ---------------------------
 
 1. Install Python 3 from [here](https://www.python.org/download/releases/) (or use brew/apt/pyenv)
 
-1. Run `make init` (this will install pip packages, use virtualenv or something similar if you don't want to install globally)
+2. Run `make init` (this will install pip packages, use virtualenv or something similar if you don't want to install globally)
 
-1. Run `make` to run the game. Run `DEBUG=True make` to see rects and coords
+3. Run `make` to run the game. Run `DEBUG=True make` to see rects and coords
 
-1. Use <kbd>&uarr;</kbd> or <kbd>Space</kbd> key to play and <kbd>Esc</kbd> to close the game.
+4. Use <kbd>&uarr;</kbd> or <kbd>Space</kbd> key to play and <kbd>Esc</kbd> to close the game.
 
-2. Optionally run `make web` to run the game in the browser (`pygbag`).
+5. Optionally run `make web` to run the game in the browser (`pygbag`).
 
 Notable forks
 -------------