[Orbital 2018 iOS Workshop] Resolving Error Encountered during Workshop

During the workshop, we encountered the following error when trying to retrieve data from Firebase: “Must call `[FIRApp configure]` (`FirebaseApp.configure( )` in Swift) before using Firebase Database.” despite the fact that we have configured FirebaseApp in the AppDelegate class. I realise that with a simple tweak in the AppDelegate class, this problem can be solved.