Just a quick not that PM2 works really well for running OF applications on RPI on startup. It requires NodeJS. It offers some flexible things for timing and keepalive. It is a much easier process than Crontab and other autostart options I have had issues with.
PM2 is also very well docomented and as a bonus you can use the log function with the app name to see the output of your app via SSH, which works better than screen for me.
Hope this helps someone.