Laravel Docker无法插入数据

Question

我正在学习docker，并且能够在生产环境中运行docker-compose。下面是我的生产文件

version: "3"

services:
  app:
    container_name: myapp
    build:
      context: .
      dockerfile: docker/Fpm.Production.Dockerfile
    working_dir: /var/www/html/dockerapps/laravel-docker-boilerplate
    volumes:
      - .:/var/www/html/dockerapps/laravel-docker-boilerplate
    links:
      - db
    networks:
      - mynet
  db:
    image: mysql:5.7
    container_name: db
    volumes:
      - dbdata:/var/lib/mysql
    environment:
      MYSQL_DATABASE: laraapp
      MYSQL_USER: laraveluser
      MYSQL_PASSWORD: laravel
      MYSQL_ROOT_PASSWORD: 123456
    networks:
      - mynet
#Volumes
volumes:
  dbdata:
    driver: local
#Docker Networks
networks:
  mynet:
    driver: bridge

.env中的数据库配置

DB_CONNECTION=mysql
DB_HOST=db
DB_PORT=3306
DB_DATABASE=laraapp
DB_USERNAME=laraveluser
DB_PASSWORD=laravel

迁移成功运行，但是当我尝试创建新用户时，遇到以下错误：

SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: No address associated with hostname (SQL: select count(*) as aggregate from `users` where `email` = user@gmail.com)

预先感谢：-）

docker ps命令的输出

CONTAINER ID        IMAGE                            COMMAND                  CREATED             STATUS              PORTS                 NAMES
a2ad106d6cd4        laravel-docker-boilerplate_app   "docker-php-entrypoi…"   21 minutes ago      Up 21 minutes       9000/tcp              myapp
b45032551712        mysql:5.7                        "docker-entrypoint.s…"   21 minutes ago      Up 21 minutes       3306/tcp, 33060/tcp   db