[FEAT] Transition to PostgreSQL database in another Docker container

docker-compose.yml

@@ -11,9 +11,11 @@ services:
     env_file:
       - .env
     volumes:
-      - ./db.sqlite3:/app/db.sqlite3:z
       - static_files:/app/static
       - media_files:/app/media
+    depends_on:
+      db:
+        condition: service_healthy
 
   caddy:
     image: caddy:2
@@ -25,15 +27,31 @@ services:
       - ./Caddyfile:/etc/caddy/Caddyfile:z
       # Caddy serves static files collected by Django
       - static_files:/srv/static:ro
-      - media_files:/srv/media:ro
+      - media_files:/srv/media
       - ./icon-192x192.png:/srv/media/icon-192x192.png:ro
       - caddy_data:/data
       - caddy_config:/config
     depends_on:
       - server
 
+  db:
+    image: postgres:15.2-alpine
+    restart: unless-stopped
+    environment:
+      POSTGRES_DB: 'breccia-mapper'
+      POSTGRES_USER: 'breccia-mapper'
+      POSTGRES_PASSWORD: ${DB_PASSWORD}
+    volumes:
+      - postgres_data:/var/lib/postgresql/data/
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U breccia-mapper"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
 volumes:
   caddy_data:
   caddy_config:
   static_files:
   media_files:
+  postgres_data: