First you have to install Postgres.app and Ruby on your computer. Then download this template, cd to it, and install the gems

$ bundle install

To run the app locally, install Shotgun and run

$ shotgun config.ru

Your app should then be running at http://localhost:9393.

Heroku relies on Git for deploying apps so initialize git for the app.

$ git init
$ git add .
$ git commit -m "Initial Commit"

To create a Heroku app, first be sure you are signed up. Then type the following in Terminal while inside of the project directory.

$ heroku create NAME_OF_YOUR_APP

Once this returns successfully, push your app to Heroku.

$ git push heroku master

If you're using DataMapper with a database, you will need to add a database. Run these commands from the root of your project, relacing the last database url with the name logged after the first command.

$ heroku addons:add heroku-postgresql:dev
$ heroku pg:promote [HEROKU_POSTGRESQL_REPLACEME_URL]

Now you've created your database. Now you need to update the tables:

$ heroku run console
$ require './app.rb'
$ DataMapper.auto_upgrade!
$ exit