added new beginner level course (#4371)

free-courses-en.md

@@ -290,6 +290,7 @@
 #### jQuery
 
 * [Bento jQuery Track](https://bento.io/topic/jquery) (Bento)
+* [Introduction to JQuery](https://www.udacity.com/course/intro-to-jquery--ud245) (Udacity)
 
 
 #### NodeJS