如何在Digital Ocean上永久运行我的MEANjs应用程序？

I've successfully just created a new droplet on Digital Ocean using their MEAN on Ubuntu 14.04 image. I can run my app from the terminal using 'grunt serve' and then view it in the browser at "ip_address:3000". But I still don't understand how I can serve it permanently, by which I mean, keep the app running even after I close my terminal. I've heard of the tool "Forever", but I don't really understand it. Do I even need it or is there another simpler way?I've successfully just created a new droplet on