To create and manage Heroku apps locally you'll need the Heroku Toolbelt, here are some ways to get it.
Download the Heroku Toolbelt installer from Heroku's website.
brew install heroku
Run this script:
wget -O- https://toolbelt.heroku.com/install-ubuntu.sh | sh
This script adds the Heroku repository to apt, installs the Heroku release key, installs the Heroku Toolbelt and then installs Ruby if you need it.
As with any script you find online and pipe directly to bash we highly recommend you read the source first.