Postmill is a neat php forum that is very similar to reddit in functionality. While not all of reddit functions are covered, like video autoplay and rewards, the rest of the good parts of reddit are. Go here and here to see it for yourself. Setting it up takes a little bit of effort, so I made a script that worked for me. Hopefully it can work for you too.
Quick Setup Script
Here is a quick script to get Postmill up and running with Ubuntu 19.10 server installed. Make sure you’ve already upgraded your system as far as possible to ensure proper packages are already installed. Respectfully stolen from nxnjz and updated. Run:
sudo bash script.sh