Merge pull request #1549 from hongchangwu/haskell

Update link for "Introduction to Functional Programming"

free-courses-en.md

@@ -67,7 +67,7 @@
 * [C9 : Functional Programming Fundamentals](http://channel9.msdn.com/Series/C9-Lectures-Erik-Meijer-Functional-Programming-Fundamentals) - Erik Meijer
 * [CIS 194: Introduction to Haskell](http://www.seas.upenn.edu/~cis194/) - Brent Yorgey
 * [CS240h: Functional Systems in Haskell](http://www.scs.stanford.edu/11au-cs240h/notes/) - Bryan O'Sullivan
-* [edX: Introduction to Functional Programming](https://www.edx.org/course/introduction-functional-programming-delftx-fp101x) - Erik Meijer
+* [edX: Introduction to Functional Programming](https://www.edx.org/course/introduction-functional-programming-delftx-fp101x-0) - Erik Meijer
 
 
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