Исправлена передача конфигурации PostgreSQL в backend

docker-compose.yml

@@ -19,7 +19,7 @@ services:
     restart: unless-stopped
     env_file: .env
     environment:
-      DATABASE_URL: postgresql+psycopg://$${POSTGRES_USER}:$${POSTGRES_PASSWORD}@db:5432/$${POSTGRES_DB}
+      DATABASE_URL: postgresql+psycopg://${POSTGRES_USER:-panel}:${POSTGRES_PASSWORD}@db:5432/${POSTGRES_DB:-panel}
     depends_on:
       db:
         condition: service_healthy