Add a reference to MyGAL in the README

Author: pvigier

README.md

@@ -4,6 +4,8 @@ A C++ implementation of the Fortune's algorithm for Voronoi diagram construction
 
 I wrote an [article](https://pvigier.github.io/2018/11/18/fortune-algorithm-details.html) about this project on my blog, feel free to read it!
 
+You may be interested by [MyGAL](https://github.com/pvigier/MyGAL) which is the follow-up of this project. I turned it into a library and fix many edge cases making it way more robust.
+
 ![Screenshot 1](https://github.com/pvigier/FortuneAlgorithm/raw/master/images/voronoi.png)
 
 ## Build