I’m building a realtime group chat app and want feedback on my backend stack before committing. Stack: Go (API + auth + business logic) Centrifugo (WebSocket realtime) Redis (pub/sub + presence + caching) PostgreSQL (messages + groups + users) Hetzner VPS (self-hosted) Docker + Nginx (deployment + reverse proxy) Is this a solid approach for a production chat app? Any improvements or missing pieces?My main goal is to handle around 50k total downloads and at least 10k active concurrent users smoothly, without message delays, lag, or stability issues during traffic spikes, while keeping infrastructure costs predictable and avoiding major rework