On Ubuntu Server 14.04 we can manage Node.js apps with the upstart service.
We need to create a .conf file in /etc/init (e.g. app.conf) with the following contents:
start on filesystem and started networking
stop on shutdown
respawn
setuid username
chdir /home/username/app
exec /usr/local/bin/node app.js
Your app will run as a service with the selected user as a owner even at boot time (and, obviously, reboot) and you will be able to manage it with the service command followed by the name of the .conf file. For example:
sudo service app restart