demo for https://github.com/jruby-gradle/jruby-gradle-jar-plugin/pull/47

build.gradle

buildscript {
  repositories {
    jcenter()     
    maven { url '/usr/local/repository' }
  }

  dependencies {
    classpath group: 'com.github.jruby-gradle', name: 'jruby-gradle-jar-plugin', version: '0.1.4-SNAPSHOT'
    classpath group: 'com.github.jruby-gradle', name: 'jruby-gradle-plugin', version: '0.1.17-SNAPSHOT'
  }
}

apply plugin: 'com.github.jruby-gradle.jar'

apply plugin: 'java'

import com.github.jrubygradle.jar.JRubyJar

task executable( type: JRubyJar ) {
  from "."
  include 'Rakefile'
  jruby {
    initScript 'blablabla.rb'
  }
}
task runnable( type: JRubyJar ) {
  from "."
  include 'Rakefile'
  include 'bla.rb'
  appendix 'runnable'
  jruby {
    initScript runnable()
  }
}

jar {
  jruby {
    defaultGems()
  }

  from "."
  include 'Rakefile'
  include 'blabla.rb'
}

dependencies {
  gems 'com.readytalk:metrics3-statsd:4.1.0'
  gems group: 'rubygems', name: 'leafy-complete', version: '0.3.1'
  gems group: 'rubygems', name: 'rake', version: '10.3.+'
}