Update free-programming-interactive-tutorials-en.md (#7900)

more/free-programming-interactive-tutorials-en.md

@@ -298,6 +298,7 @@
 ### NoSQL
 
 * [MongoDB Koans](https://github.com/chicagoruby/MongoDB_Koans)
+* [MongoDB Tutorial](https://www.w3schools.com/mongodb) - W3Schools
 * [Try Redis](http://try.redis.io)