jspm bundle task for gulp

bundle.js

var gulp = require('gulp');  
var paths = require('../paths');  
var jspm = require('jspm/api');

gulp.task('bundle', function (done) {  
  jspm.bundle(
    [
      '*',
      'aurelia-skeleton-navigation/*',
      'aurelia-bootstrapper',
      'aurelia-http-client',
      'aurelia-dependency-injection',
      'aurelia-router'
    ].join(' + '),
    'bundle/app-bundle.js',
    {inject:true, minify: true}
  ).then(function () {
    gulp.src('./bundle/app-bundle.js')
      .pipe(gulp.dest(paths.output + 'bundle/'));
    done();
  });
});