Merge pull request #1534 from iKenshu/add-free-course

Add free courses

free-courses-en.md

@@ -6,6 +6,7 @@
 * [C++](#c-1)
 * [Clojure](#clojure)
 * [Databases](#databases)
+* [Git](#git)
 * [Haskell](#haskell)
 * [HTML / CSS](#html--css)
 * [iOS](#ios)
@@ -16,7 +17,9 @@
 * [OCaml](#ocaml)
 * [Oracle PL/SQL](#oracle-plsql)
 * [Python](#python)
+* [RethinkDB](#rethinkdb)
 * [Ruby](#ruby)
+* [Sails.js](#sailsjs)
 * [Scala](#scala)
 * [Swift](#swift)
 * [Web Development](#web-development)
@@ -53,6 +56,8 @@
 * [Database Systems](http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-830-database-systems-fall-2010/) (MIT's opencourseware)
 * [Introduction to Databases](https://class.stanford.edu/courses/Engineering/db/2014_1/about) (Stanford University)
 
+### Git
+*[Git and Gitlab Live Workshop](https://courses.platzi.com/courses/git-gitlab/)
 
 ### Haskell
 * [C9 : Functional Programming Fundamentals](http://channel9.msdn.com/Series/C9-Lectures-Erik-Meijer-Functional-Programming-Fundamentals) - Erik Meijer
@@ -124,10 +129,14 @@
 * [Google's Python Course](https://developers.google.com/edu/python/)
 * [Introduction to Computer Science and Programming](http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-00sc-introduction-to-computer-science-and-programming-spring-2011/) (MIT's opencourseware)
 
+### RethinkDB
+* [RethinkDB: Distributed Databases](https://courses.platzi.com/courses/rethinkdb-databases/)
 
 ### Ruby
 * [RubyMonk - Interactive Ruby tutorials](http://rubymonk.com)
 
+### Sails.Js
+* [Develop web apps in Node.js and Sails.js](https://courses.platzi.com/courses/develop-apps-sails-js/)
 
 ### Scala
 * [Functional Programming Principles in Scala](https://www.coursera.org/course/progfun)