Automated Signing of *.*.apk file in Android Studio

gradle-android-signing.gradle

def Properties props = new Properties()
def propFile = file('../signing.properties')
if (propFile.canRead()){
    props.load(new FileInputStream(propFile))

    if (props!=null && props.containsKey('STORE_FILE') && props.containsKey('STORE_PASSWORD') &&
            props.containsKey('KEY_ALIAS') && props.containsKey('KEY_PASSWORD')) {

        println 'RELEASE BUILD SIGNING'

        android.signingConfigs.release.storeFile = file(props['STORE_FILE'])
        android.signingConfigs.release.storePassword = props['STORE_PASSWORD']
        android.signingConfigs.release.keyAlias = props['KEY_ALIAS']
        android.signingConfigs.release.keyPassword = props['KEY_PASSWORD']
    } else {
        println 'RELEASE BUILD NOT FOUND SIGNING PROPERTIES'

        android.buildTypes.release.signingConfig = null
    }
}else {
    println 'RELEASE BUILD NOT FOUND SIGNING FILE'
    android.buildTypes.release.signingConfig = null
}