Add 'Write yourself a Git!'

README.md

@@ -215,6 +215,7 @@
 * [**JavaScript**: _Gitlet_](http://gitlet.maryrosecook.com/docs/gitlet.html)
 * [**JavaScript**: _Build GIT - Learn GIT_](https://kushagragour.in/blog/2014/01/build-git-learn-git/)
 * [**Python**: _Just enough of a Git client to create a repo, commit, and push itself to GitHub_](https://benhoyt.com/writings/pygit/)
+* [**Python**: _Write yourself a Git!_](https://wyag.thb.lt/)
 * [**Ruby**: _Rebuilding Git in Ruby_](https://robots.thoughtbot.com/rebuilding-git-in-ruby)
 
 #### Build your own `Network Stack`