Prepares production for SQLite → PostgreSQL migration:
- Add postgres service (mitai-db, port 5432)
- Add DB environment variables to backend
- Backend depends on postgres health check
- Uses startup.sh for automatic migration
Migration strategy:
1. SQLite data in /app/data/bodytrack.db is preserved (volume mounted)
2. On first start with empty PostgreSQL: automatic migration
3. Migration is safe: checks if profiles table is empty before migrating
4. After migration: all new data goes to PostgreSQL
IMPORTANT: Set DB_PASSWORD in .env before deploying!
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
