It's like Laravel Spark, for Rails. All your Rails apps should start off with a bunch of great defaults.

Jumpstart is a Rails template, so you pass it in as an option when creating a new app.

rails new myapp -d postgresql -m https://raw.githubusercontent.com/excid3/jumpstart/master/template.rb

Or if you have downloaded this repo, you can reference template.rb locally:

rails new myapp -d postgresql -m template.rb

rails db:drop
spring stop
cd ..
rm -rf myapp