Reloading a Cordova project with Grunt

Gruntfile.js

module.exports = function(grunt) {

  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    watch: {
        src: {
            files: ['www/**/*.html', 'www/**/*.js', 'www/**/*.css'],
            tasks: ['shell']
        }
    }, 
    shell: {
      cordova_prepare: {
        command: "cordova prepare"
      }
    }
  });

  grunt.loadNpmTasks('grunt-shell');
  grunt.loadNpmTasks('grunt-contrib-watch');

  grunt.registerTask('default', ['watch']);

};

package.json

{
  "name": "app_name",
  "version": "1.0.0",
  "devDependencies": {
    "grunt": "~0.4.5",
    "grunt-contrib-watch": "^0.6.1",
    "grunt-shell": "^1.0.1"
  }
}