add postgres db, use settings and user data, lots of cleanup and logic fixes, bug fixes, better error handling, update docs and docker

docker-compose.yml.example

@@ -6,4 +6,16 @@ services:
     volumes:
       - ./.env:/usr/src/app/.env:ro
     environment:
-      - NODE_ENV=production
+      - NODE_ENV=production
+  postgres:
+    image: postgres:17
+    container_name: kowalski-postgres
+    restart: unless-stopped
+    ports:
+      - 5433:5432
+    volumes:
+      - ./db:/var/lib/postgresql/data
+    environment:
+      - POSTGRES_USER=kowalski
+      - POSTGRES_PASSWORD=kowalski
+      - POSTGRES_DB=kowalski