Node JS on Boot

I am running a raspberry pi B+ with the intentions of running a node js app on boot.

I am using the command su pi -c 'node /home/pi/bartender_main/app.js < /dev/null &' in my /etc/rc.local file. When it boots up it act like it work and give me my indication that it is ready, but shortly is says board closing and it quits the app. Does anyone have any ideas. Thanks