Migrate docker compose to directly use env file

docker-compose.yml

@@ -3,17 +3,8 @@ services:
     image: vaultwarden/server:1.31.0
     container_name: vaultwarden
     restart: unless-stopped 
-    environment:
-      - WEBSOCKET_ENABLED=true # Enable WebSocket notifications.
-      - SIGNUPS_ALLOWED=false
-      - DOMAIN=${DOMAIN}
-      - SMTP_HOST=${SMTP_HOST}
-      - SMTP_FROM=${SMTP_FROM}
-      - SMTP_PORT=587
-      - SMTP_SSL=true
-      - SMTP_USERNAME=${SMTP_USERNAME}
-      - SMTP_PASSWORD=${SMTP_PASSWORD}
-      - ADMIN_TOKEN=${ADMIN_TOKEN}
+    env_file:
+      - .env
     volumes:
       - ./bw-data:/data
     networks: