I have deleted google-services.json. Add yours
Implementation Guide
1 - Project
1 - Open the Project in your android studio;
2 - IMPORTANT Change the Package Name. (https://stackoverflow.com/questions/16804093/android-studio-rename-package)
2 - Firebase Panel
1 - Create Firebase Project (https://console.firebase.google.com/);
2 - import the file google-service.json into your project