Upgrading Ghost

So I setup putty to SSH to my server few days weeks back and I really wanted to try something out since I din't have linux on my computer anymore. And I happened to visit the Ghost website and noticed that Ghost was now 0.7 while I had 0.6 installed. For those who don't know ghost, it's the blogging platform I'm using for this blog. You can either get a Ghost Pro account and let them do the installing, maintaining, etc. or set it up and manage the blog yourself. Since I'm self-hosting, I had to upgrade it manually.

I followed the upgrade guide here. At the end of it, I was glad I had taken a backup of the data. Because all I saw was this:
Image - 502 Bad Gateway

So I knew that something was wrong, but wasn't sure what. Tried google and found a lot of links. Some of them were as recent as a month back. But none of them worked.

That's when I noticed that running ghost by sudo service ghost start wasn't working, but running it with npm start worked. So I ended up running ghost using forever.