Version names for application variants

flavor_names_build.gradle

android {
  applicationVariants.all { variant ->
    def flavor = variant.mergedFlavor
    def name = flavor.getVersionName()
    def versionName = name + '-' + variant.properties.get('flavorName')
    if (variant.buildType.isDebuggable()) {
       versionName += '-debug';
    }
    flavor.versionName = versionName;
  }
}