Merge pull request #1251 from hongchangwu/master

Add free course - Functional programming with Clojure
looks good, thanks!

free-courses-en.md

@@ -2,6 +2,7 @@
 * [Assembly](#assembly)
 * [Android](#android)
 * [C++](#c)
+* [Clojure](#clojure)
 * [Databases](#databases)
 * [Haskell](#haskell)
 * [HTML / CSS](#html--css)
@@ -34,6 +35,10 @@
 * [LearnCpp.com C++ Tutorial](http://www.learncpp.com/)
 
 
+### Clojure
+* [Functional Programming with Clojure](http://mooc.cs.helsinki.fi/clojure)
+
+
 ### Databases
 * [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)