Git Tutorial Added (#6290)

* Git Tutorial Added

* update the name

* revert back

* move to book

books/free-programming-books-langs.md

@@ -770,6 +770,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 
 ### Git
 
+* [A git Primer](https://danielmiessler.com/study/git/) - Daniel Miessler
 * [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 - the simple guide](http://rogerdudler.github.io/git-guide/)