Add "Learn Git".

free-programming-books.md

@@ -823,6 +823,7 @@
 * [Git Succinctly, Syncfusion](http://www.syncfusion.com/resources/techportal/ebooks/git) (PDF, Kindle) *(Just fill the fields with any values)*
 * [git - the simple guide](http://rogerdudler.github.io/git-guide/)
 * [Git Workflows](http://documentup.com/skwp/git-workflows-book)
+* [Learn Git - Learn Version Control with Git](http://www.git-tower.com/learn/ebook/command-line/introduction#start) - Tobias Günther
 * [Pro Git](http://git-scm.com/book) - Scott Chacon
 * [Pro Git Reedited](https://leanpub.com/progitreedited) - Jon Forrest
 * [Think Like (a) Git: A Guide for the Perplexed](http://think-like-a-git.net)