Set ruby version and trim Gemfile
Disable sessions

With the exception of Licensing, our frontend apps don't use sessions. They are
stripped off requests and responses by our Varnish configuration.

Therefore this should make dev more like production and avoid accidentally
introducing a dependency on sessions.
Add rspec

I need to write a spec for a healthcheck route.
Add a healthcheck route

When we configure the app with Puppet and deploy the app to an environment, a
monitoring check will automatically be created which uses this route.
Add jenkins.sh
Add Airbrake
Disable Rails frameworks we know we won't use
Add Unicorn for running the app in production mode
Add logstasher for logging
Set assets prefix

We will have some of our own assets. This corresponds to:
https://github.gds/gds/alphagov-deployment/blob/9d0ee17fb94399e9b63ce7baebc0164a51911bc2/courts-frontend/config/deploy.rb#L13
Add startup.sh
Merge pull request #1 from alphagov/bootstrapping

Bootstrapping