Adding section for memory allocators and adding a first tutorial for it

README.md

@@ -231,6 +231,10 @@ It's a great way to learn.
 * [**Python**: _ugit: Learn Git Internals by Building Git Yourself_](https://www.leshenko.net/p/ugit/)
 * [**Ruby**: _Rebuilding Git in Ruby_](https://robots.thoughtbot.com/rebuilding-git-in-ruby)
 
+#### Build your own `Memory Allocator`
+
+* [**C**: _Malloc is not magic -- Implementing your own memory allocator_](https://medium.com/p/e0354e914402)
+
 #### Build your own `Network Stack`
 
 * [**C**: _Beej's Guide to Network Programming_](http://beej.us/guide/bgnet/)