Provide detailed instructions for users to host the application themselves

Adds deployment guide and download instructions for self-hosting the application with Node.js, PostgreSQL, and necessary configurations.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 52666613-a8ed-48cb-bd60-b29f2edda00f
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/590c3f3c-a47c-4ee0-8c1c-090eca062bfb/52666613-a8ed-48cb-bd60-b29f2edda00f/DvtyaYX
