Go to firebase.google.com and create a new project, choose getting started with iOS app.
Register for the app, add iOS bundle ID
from XCode. For example:
com.example.chat-app
Download GoogleService-Info.plist
file and add it into the project directory.
Install Cocoapods:
$ sudo gem install cocoapods
Create a Podfile if you don't have one:
$ pod init
Open your Podfile and add:
$ pod 'Firebase/Core'
$ pod 'Firebase/Core'
$ pod 'Firebase/Database'
$ pod 'Firebase/Auth'
$ pod 'Firebase/Storage'
Save the file and run:
$ pod install