轨道5与美洲狮与nginx systemd

right now i have a droplet in DO and experimenting in rails deployment procedures. I have a rails 5 in ubuntu 16 and have done all necessary procedures to be able to deploy my app except that currently stuck in nginx puma and systemd. I've already seen DO's tutorials but the problem is that they use upstart as the script for init. As a complete beginner in nginx and linux systems, i have no idea how to start my app with nginx. the last procedures i made wasright now i have a droplet in DO and experiment