Readd erlang author

free-programming-books.md

@@ -527,7 +527,7 @@
 
 ###Erlang
 * [Études for Erlang](http://chimera.labs.oreilly.com/books/1234000000726/index.html) - J. David Eisenberg
-* [Learn You Some Erlang For Great Good](http://learnyousomeerlang.com/)
+* [Learn You Some Erlang For Great Good](http://learnyousomeerlang.com/) - Frederic Trottier-Hebert
 * [Concurrent Programming in ERLANG](http://www.erlang.org/download/erlang-book-part1.pdf)