adding 'Git for Computer Scientists'

free-programming-books.md

@@ -952,6 +952,7 @@ Original Source: [Free Programming books](http://stackoverflow.com/revisions/392
 * [A practical git introduction](http://mrchlblng.me/2014/09/practical-git-introduction/)
 * [A Visual Git Reference](http://marklodato.github.io/visual-git-guide/index-en.html) - Mark Lodato
 * [Conversational Git](http://blog.anvard.org/conversational-git/)
+* [Git for Computer Scientists](http://eagain.net/articles/git-for-computer-scientists/)
 * [Git From The Bottom Up](http://ftp.newartisans.com/pub/git.from.bottom.up.pdf) (PDF)
 * [Git Immersion](http://gitimmersion.com)
 * [Git internals](https://github.com/pluralsight/git-internals-pdf/raw/master/drafts/peepcode-git.pdf) - Scott Chacon (PDF)