Add .env file support to docker-compose configurations

Added the `env_file` directive to both `docker-compose.yml` and `docker-compose.dev.yml` to load environment variables from a `.env` file. This ensures consistent environment variable management across different configurations.

docker-compose.yml

@@ -21,6 +21,8 @@ services:
       context: ./backend
       dockerfile: Dockerfile
       target: production
+    env_file:
+      - .env
     environment:
       - DATABASE_URL=${DATABASE_URL}
       - SECRET_KEY=${SECRET_KEY}