You must sign up for a free account on http://back4app.com in order to create a App on back{4}app, grab its App and Client Keys and paste them the Configs.swift file of this app.

back{4}app service offers the following FREE features for the STARTER pack:
• 1 GB Database Storage
• 5 GB File Storage
• 10 Requests/second
• 50 K Requests/month
• 1 Cloud Code Job

Check out its PRICING tables here: https://www.back4app.com/pricing/

Here you can find DOCS: http://docs.back4app.com/

Read this tutorial to learn how to rename a package name in Android Studio: https://hubpages.com/technology/Android-How-to-rename-an-app-package