Added License (#11748)

* Added License

* Update free-programming-books-langs.md

* Update books/free-programming-books-langs.md

Co-authored-by: Eric Hellman <eric@hellman.net>

---------

Co-authored-by: Eric Hellman <eric@hellman.net>

books/free-programming-books-langs.md

@@ -614,7 +614,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [CoffeeScript Cookbook](https://coffeescript-cookbook.github.io)
 * [CoffeeScript Ristretto](https://leanpub.com/coffeescript-ristretto/read) - Reginald Braithwaite
 * [Hard Rock CoffeeScript](https://alchaplinsky.github.io/hard-rock-coffeescript/) - Alex Chaplinsky (gitbook)
-* [Smooth CoffeeScript](http://autotelicum.github.io/Smooth-CoffeeScript/SmoothCoffeeScript.html)
+* [Smooth CoffeeScript](http://autotelicum.github.io/Smooth-CoffeeScript/SmoothCoffeeScript.html) (CC BY)
 * [The Little Book on CoffeeScript](http://arcturo.github.io/library/coffeescript/) - Alex MacCaw, David Griffiths, Satoshi Murakami, Jeremy Ashkenas