how to log with groovy and gradle

Needed files:

• build.gradle
• HelloWorld.groovy

MY_PROJECT_DIR/build.gradle

apply plugin:'groovy'
apply plugin:'application'

repositories {
mavenCentral()
}

ext.logbackVersion = '1.0.7'
ext.slf4jVersion = '1.7.0'
ext.groovyVersion = '2.0.2'

dependencies {
groovy "org.codehaus.groovy:groovy:$ext.groovyVersion"
compile "org.slf4j:slf4j-api:$ext.slf4jVersion"
compile "ch.qos.logback:logback-classic:$ext.logbackVersion"
}

mainClassName = "HelloWorld"


MY_PROJECT_DIR/src/main/groovy/HelloWorld.groovy
import groovy.util.logging.Slf4j

@Slf4j
class HelloWorld {

HelloWorld() {
log.info 'Hello World'
}

static main(args) {
new HelloWorld()
}
}