Basic start/stop upstart init conf for a ruby script. May require modification to run in /bin/bash or if you need to source rbenv or chruby.

ruby-example-upstart.conf

# /etc/init/ruby-example-upstart.conf

description "Ruby example upstart conf"

# change to the user you want to run this ruby script as
setuid deploy
setgid deploy

# This starts upon bootup and stops on shutdown
# check runlevel of running system with `runlevel` command
start on runlevel [2345]
stop on runlevel [06]

# controls for respawning this process if it dies
respawn # yes, we want this to respawn
respawn limit 3 30 # only try 3x to respawn in 30 seconds

# Setup any env variable you want to use, you can also pass variables into the start/stop
env RAILS_ENV=production

# pre-start script
  # use this for any pre-start stuff
# end script

script

  # give us a login shell to load rbenv/chruby, YMMV
  exec /bin/bash -lc <<EOS
    cd /where/the/ruby/script/is
    exec bin/ruby-script -e ${RAILS_ENV} # or whatever params you need
  EOS

end script