Restart River5 after Reboot with PM2

I run a River5 “River of News” on a Raspberry Pi wirelessly connected to my internal home network. Sometimes, the power fluctuates, and the Pi reboots. I want to have River5 restart when the system comes back up. There are lots of ways to restart stuff on Linux. (I am running Raspian GNU/Linux 8.0.) The process manager I use is PM2 – mostly because it knows Nodejs. River5 is written for Node.