Update README.md

add documentation section in README.md

README.md

@@ -18,6 +18,10 @@ Optional:
 * Python 3
 * Pillow
 
+## Documentation
+
+For more information about the code, please read [the documentation](https://raph080.github.io/gbSnake/html/index.html).
+
 ## Getting Started
 
 1. Make sure gcc and make are installed
@@ -103,4 +107,4 @@ If you want to compose your own for this game, feel free to try [OpenMPT](https:
 * https://blog.flozz.fr/2018/10/01/developpement-gameboy-1-hello-world/
 * http://modp3.mikendezign.com
 * https://modarchive.org
-* https://itch.io/game-assets/tag-gameboy/tag-music
+* https://itch.io/game-assets/tag-gameboy/tag-music