Add "Hard Rock CoffeeScript"

Added "Hard Rock CoffeeScript" and link

Author: chauxvive

books/free-programming-books-langs.md

@@ -569,6 +569,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 
 * [CoffeeScript Cookbook](https://coffeescript-cookbook.github.io)
 * [CoffeeScript Ristretto](https://leanpub.com/coffeescript-ristretto/read) - Reginald Braithwaite  *(Leanpub account or valid email requested)*
+* [Hard Rock CoffeeScript](https://alchaplinsky.github.io/hard-rock-coffeescript/)
 * [Smooth CoffeeScript](http://autotelicum.github.io/Smooth-CoffeeScript/SmoothCoffeeScript.html)
 * [The Little Book on CoffeeScript](http://arcturo.github.io/library/coffeescript/)