Add tutorial about how to write your own git

Add tutorial about how to write your own git like source control system in Python by Thibault Polge.

Author: bobeff

README.md

@@ -452,6 +452,7 @@ To get started, simply fork this repo. Please refer to [CONTRIBUTING.md](CONTRIB
  - [Part 3](http://www.ardendertat.com/2011/07/17/how-to-implement-a-search-engine-part-3-ranking-tf-idf/)
 - [Build the Game of Life](https://robertheaton.com/2018/07/20/project-2-game-of-life/)
 - [Create terminal ASCII art](https://robertheaton.com/2018/06/12/programming-projects-for-advanced-beginners-ascii-art/)
+- [Write yourself a Git](https://wyag.thb.lt/)
 
 ## Go: