gistfile1.txt

buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
            firebaseAppDistribution {
                releaseNotesFile="$projectDir/apprelease/releasebuild/release_note.txt"
                //----------------OR---------
                //releaseNotes="Here is new app release note"

                testersFile="$projectDir/apprelease/releasebuild/testers.txt"
                //----------------OR---------
                //testers ="tester1@gmail.com,tester2@gmail.com"

                groupsFile="$projectDir/apprelease/releasebuild/firebase_group.txt"
                //----------------OR---------
                //groups ="qa-team, android-testers"
            }
        }
        debug{
            firebaseAppDistribution {
                releaseNotesFile="$projectDir/apprelease/debug/release_note.txt"
                //----------------OR---------
                //releaseNotes="Here is new app release note"

                testersFile="$projectDir/apprelease/debug/testers.txt"
                //----------------OR---------
                //testers ="tester1@gmail.com,tester2@gmail.com"

                groupsFile="$projectDir/apprelease/debug/firebase_group.txt"
                //----------------OR---------
                //groups ="qa-team, android-testers"
            }
        }
    }
}