Example with Firebase 3.9

[atlewee]

Hi, I have never ever created a pull Request in my life. Don't know exactly how git works yet :) Hope this is the correct way of suggesting stuff. I just started coding, for fun. Don't know if this is interesting, but this is atl east one working way to use the newest version of Firebase ? It seems to work just fine here with valueChanged from the Example.

Want to learn and be of assistance in the future, just don't know how yet :)