in order to add to ur app:

• create new app on firebase console and get build ID
• need these in ur Podfile
  • pod 'Firebase/Core'
  • pod 'Firebase/Database'
  • pod 'Firebase/Analytics'
  • pod 'Firebase/Firestore'
  • pod 'FirebaseFirestoreSwift'
• "GoogleService-Info.plist" in same folder as AppDelegate.swift
• add "import Firebase" and "FirebaseApp.configure()" in AppDelegate.swift