Added egghead.io in free courses

free-courses-en.md

 ###Index
 * [Databases](#databases)
 * [HTML / CSS](#html--css)
+* [JS](#js)
 * [iOS](#ios)
 * [Oracle PL/SQL](#oracle-plsql)
 * [Ruby](#ruby)
@@ -14,6 +15,9 @@
 * [Learn HTML5 Programming From Scratch](https://www.udemy.com/learn-html5-programming-from-scratch/)
 
 
+###JS
+* [Egghead.io](https://egghead.io/)
+
 ###iOS
 * [Developing iOS 7 Apps for iPhone and iPad](https://itunes.apple.com/us/course/developing-ios-7-apps-for/id733644550) (slides and videos) - Stanford University