gruntfile.js

module.exports = function(grunt) {

  // Project configuration.
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    browserify: {
      libs:{
        files: {
        "app/assets/javascripts/lib.js": ["app/assets/javascripts/libs/*.js"]
        },
        options: {
          alias:[
              "./bower_components/angular/angular.js:angular", "./bower_components/lodash/dist/lodash.js:lodash"],
          shim:{

            jquery:{
              path:"./bower_components/angular/angular.js",
              exports:"angular"
            },

            underscore:{
              path:"./bower_components/lodash/dist/lodash.js",
              exports:"_"
            },
          }
        }
      },
      app: {
        files: {
          'app/assets/javascripts/app.js': ['app/assets/javascripts/app/**/*.coffee'],
        },

        options: {
          transform: ['coffeeify'],
          alias:[
            "./bower_components/angular/angular.js:angular", "./bower_components/lodash/dist/lodash.js:lodash"
            ],
          external:["./bower_components/angular/angular.js", "./bower_components/lodash/dist/lodash.js"],
        }
      },

    watch: {

      browserify:{
        files: ["app/assets/javascripts/**/**/**/*.coffee", "spec/javascripts/modules/*.coffee"],
        tasks: ['browserify:app']
      },


    }
  });

  require('load-grunt-tasks')(grunt);

  // Runs both browserify tasks
  grunt.registerTask('default', ['browserify']);
  grunt.registerTask('libs', ['browserify:libs']);

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

};

package.json

{
  "name": "Test",
  "version": "0.1.0",
  "repository": {
    "type": "git",
    "url": "..."
  },
  "devDependencies": {
    "grunt": "~0.4.2",
    "grunt-contrib-coffee": "~0.7.0",
    "grunt-contrib-watch": "~0.5.3",
    "load-grunt-tasks": "~0.2.1",
    "grunt-contrib-clean": "~0.5.0",
    "browserify": "~3.28.2",
    "grunt-browserify": "~1.3.0",
    "grunt-coffeeify": "~0.1.3",
    "through": "~2.3.4",
    "duplexer": "~0.1.1"
  },
  "dependencies": {
    "underscore": "~1.6.0",
    "jquery": "~1.11.0",
  }
}