授予php-fpm容器权限以在docker-compose中写入文件

Question

我如何授予php-fpm容器权限以将文件写入目录？

docker-compose.yml文件：

version: '3'
services:
  web:
    image: nginx:latest
    ports:
      - "8080:80"
    volumes:
      - ./code:/code
      - ./site.conf:/etc/nginx/conf.d/default.conf
      - ./logs:/var/log/nginx
    restart: always
    depends_on:
      - php
  php:
    image: bitnami/php-fpm:7.1
    volumes:
      - ./custom.ini:/opt/bitnami/php/etc/conf.d/custom.ini
      - ./code:/code
  db:
    image: postgres:10.1
    restart: always
    environment:
      - POSTGRES_DB=${DB_NAME}
      - POSTGRES_USER=${DB_USER}
      - POSTGRES_PASSWORD=${DB_PASSWORD}
    ports:
      - 5400:5432

当docker-compose启动时，我尝试运行我的代码，但是出现一个错误，提示php没有写文件的权限：

PHP message: PHP Warning:  mkdir(): Permission denied in /code/vendor/yiisoft/yii2/helpers/BaseFileHelper.php on line 624" while reading upstream, client: 10.0.2.2, server: , request: "GET / HTTP/$
2018/11/24 09:35:25 [error] 6#6: *2 FastCGI sent in stderr: "PHP message: An Error occurred while handling another error:
yii\base\InvalidConfigException: The directory is not writable by the Web process: /code/assets/runtime in /code/vendor/yiisoft/yii2/web/AssetManager.php:215