Development

npm install
grunt
node app // or, grunt nodemon

Deployment

Use the nodejs-grunt buildpack:

heroku create twitter-search --buildpack https://github.com/mbuchetics/heroku-buildpack-nodejs-grunt
git push heroku master

You can always set the buildpack config variable separately:

heroku config:add BUILDPACK_URL=https://github.com/mbuchetics/heroku-buildpack-nodejs-grunt.git