What this buildpack does

Run npm install
Install latest version of gulp if a gulpfile is present and was not already installed by previous pass
Install latest version of bower if a bowerfile is present and was not already installed by previous pass
Install latest version of grunt if a gruntfile is present and was not already installed by previous pass
Install bundle
Run bower install
Run bundle install
Run bundle exec compass compile
Run gulp heroku:$NODE_ENV (by default, it expands to heroku:production)
Run grunt heroku:$NODE_ENV

How to access private repos

Currently we support private repos for bower, for GitHub, by leveraging the "shorthand syntax". Follow this guide:

In your bower.json, install private repos using the syntax "organization/repo".
Create or modify your .bowerrc file, adding this line: "shorthand-resolver": "git@github.com:{{owner}}/{{package}}.git". This tells bower to normally access GitHub using SSH, so that you have access to your private repos.
Create a personal access token from your GitHub account security page. Unfortunately, GitHub doesn't allow to limit the token to access to a specific repo (nor a specific organization). If you feel uncomfortable with this, you need to create a new dummy GitHub user, grant it access to the repo(s) that you need to access from Heroku, and then create a personal access token for this user.
Save the token in the Heroku enviornment as GITHUB_AUTH_TOKEN.

The buildpack will then automatically instruct bower to access your repos through the token instead of using SSH (for which it wouldn't have access).

Everything is cached after first download: npm, bower, gems
If you're upgrading from another grunt/gulp/bower/nodejs buildpack/fork, the process might fail because of a different use of the build cache. You're advised to purge the build cache of your project, by running: heroku plugins:install https://github.com/heroku/heroku-repo.git; heroku repo:purge_cache -a appname