Android / Gradle - copy apk to folder for backup after assemble. Should be run manually ( `$./gradlew assemble backupApks` )

build.gradle

// Copy assembled apks into TEST_BACKUP (must run manually)
task backupApks(type: Copy) {
  if (project.hasProperty("TEST_BACKUP")) {
    println "Backing up apks..."

    from('build/outputs/apk/')
    include '*prod-release.apk'
    include '*prod-staging.apk'
    into "${project.getProperty("TEST_BACKUP")}"
  } else {
    println "No backup done because TEST_BACKUP gradle variable is not defined."
  }
}