fix：修复docker挂载封面目录问题

Author: xiamuceer-j

README.md

@@ -277,6 +277,7 @@ services:
     volumes:
       - ./logs:/app/logs
       - ./.env:/app/.env:ro
+      - ./storage/generated_covers:/app/backend/storage/generated_covers
     environment:
       # 应用配置
       - APP_NAME=${APP_NAME:-MuMuAINovel}

docker-compose.yml

@@ -62,6 +62,7 @@ services:
       - "${APP_PORT:-8000}:8000"
     volumes:
       - ./logs:/app/logs
+      - ./storage/generated_covers:/app/backend/storage/generated_covers
       - ./.env:/app/.env:ro
     environment:
       # 应用配置