Use https url

README.md

 * [Elasticsearch: The Definitive Guide](https://www.elastic.co/guide/index.html) - A guide to working with Elasticsearch by Clinton Gormley and Zachary Tong.
 * [Eloquent JavaScript](http://eloquentjavascript.net/) - A book about JavaScript programming by Marijn Haverbeke.
 * [Vagrant Cookbook](https://leanpub.com/vagrantcookbook) - A book about creating Vagrant environments by Erika Heidi.
-* [Pro Git](http://git-scm.com/book/en/v2) - A book about Git by Scott Chacon and Ben Straub.
+* [Pro Git](https://git-scm.com/book/en/v2) - A book about Git by Scott Chacon and Ben Straub.
 * [Head First Design Patterns](http://www.headfirstlabs.com/books/hfdp/) - A book that expains software design patterns.
 
 ## PHP Videos