Added I Love Ruby official website (#2169)

Added I love ruby official website so that people can get latest updated book every time. This was done because I consider dropbox as a spyware and so have moved to openmailbox for my book distribution.

free-programming-books.md

@@ -1929,7 +1929,7 @@ For resources on Angular, Backbone, D3, Dojo, Ember, Express, jQuery, Knockout,
 * [A community-driven Ruby style guide](https://github.com/bbatsov/ruby-style-guide)
 * [CodeCademy Ruby](https://www.codecademy.com/learn/ruby)
 * [Developing Games With Ruby](https://leanpub.com/developing-games-with-ruby/read)
-* [I Love Ruby](http://goo.gl/1qrMUN)
+* [I Love Ruby](https://mindaslab.github.io/I-Love-Ruby/)
 * [Introduction to Programming with Ruby](https://launchschool.com/books/ruby) - Launch School
 * [Just Enough Ruby to Get By](http://jasonkim.ca/projects/just_enough_ruby_to_get_by/)
 * [Learn Ruby the hard way](http://learnrubythehardway.org/book/)