This buildpack will handle installing Bower dependencies for your app.
Unless you're deploying a very boring application that has no backend stack (Node.js / Play / Rails / Django / whatever), you're going to want to use this buildpack along with your primary buildpack. You do that by using heroku-buildpack-multi.
Assuming your application is Node.js, using this buildpack along with the Node.js buildpack is as simple as checking in a
.buildpacks file into your repository...
$ cat .buildpacks https://bitbucket.org/sday_atlassian/heroku-buildpack-bower.git#master https://github.com/heroku/heroku-buildpack-nodejs.git#master
... and then updating your Heroku app to use the heroku-buildpack-multi buildpack.
$ heroku config:add BUILDPACK_URL=https://github.com/ddollar/heroku-buildpack-multi.git
This buildpack will vendor a private copy of Node.js to run Bower. The Node.js install is fetched from Heroku's CDN, so it takes approx ~1 second to download the tarball and extract it. It caches the install of Bower into your slug to speed up the install process. It also configures Bower to use your slugs cache for the packages + registry metadata, so subsequent re-deploys are very quick. Finally, it (temporarily) uses a forked verison of Bower that ensures Bower doesn't croak due to crazy ENOENT / ENOTEMPTY issues during deploy.
Without this buildpack you have two options:
bower_components/directory in to the repo.
postinstallstep that runs bower.
Copy the snippet above into CLI.