For the supabase hackathon recently me and 2 others made a chat app for GitHub repositories!
It uses supabase's auth, database, storage and the realtime features and is open-source itself - https://github.com/HarryET/github-chat.
Any support is awesome and I'm still actively working on new features like bots & profile UIs (an example for the profile UIs is here https://ghc.pw/harry)