flavor.groovy

android {
    .....

    flavorDimensions "appType" //Can be anything, just identifier
    productFlavors {
        Client {
            dimension "appType"
            applicationIdSuffix ".client" //Will be added to package name of the app, making the app unique

            //More can be added like
            versionCode 1
            versionName "1.0"
        }

        Rider {
            dimension "appType"
            applicationIdSuffix ".rider" //As said above

            //More can be added like
            versionCode 1
            versionName "1.0"
        }
    }
    ...
}