Dynamic Website on a Pi

Hi! So I'm using an open source RSS aggregator self hosted alongside my pi-hole.

Anyone know how the basics of making a website go from static to dynamic work? What I want to do is add more RSS feeds from any device on my network and have the changes synced network-wide. Right now though, adding feeds is stored as a local cookie on each device separately.

Here is the repository I'm looking at: https://github.com/sempostma/newsfeeder

Any ideas on how I can store the feeds info on the Pi instead?