Start Application on boot Ubuntu

I am trying to make my application (OpenProject) starting with the
system boot, but to test the script as root, returns me the error:

/usr/bin/env:ruby: No such file or directory.

My script is like this:

#!/bin/bash
RAILS_ENV="production"
cd/home/openproject/openproject
su -c openproject "bundle exec rails server"

Someone help?