Laravel エラー SQLSTATE[HY000] [2002] php_network

####環境　

Laravel5.6
php7.1
mysql5.7

現在Dockerで環境を構築し、ログイン画面を作っていたのですが、アドレスとPWはあっているのですが、ログインをしようとすると以下のエラー文が出てしまいます。

SQLSTATE[HY000] [2002] php_network_getaddresses: 
getaddrinfo failed: nodename nor servname provided, or not known 
(SQL: select * from `users` where `email` = youyou@youyou.co.jp limit 1)

叩いた seeder

php
1
2<?php
3
4use Illuminate\Database\Seeder;
5use App\User;
6
7
8class UserTableSeeder extends Seeder
9{
10    /**
11     * Run the database seeds.
12     *
13     * @return void
14     */
15    public function run()
16    {
17        $user = new User();
18        $user->name = 'admin';
19        $user->email = 'youyou@youyou.co.jp';
20        $user->password = bcrypt('you42');
21        $user->save();
22    }
23}

mysql内のテーブル
パスワードはbcryptで暗号化

sql
1mysql> select * from users
2+----+-------+-------------------------+--------------------------------------------------------------+----------------+---------------------+---------------------+
3| id | name  | email                   | password                                                     | remember_token | created_at          | updated_at          |
4+----+-------+-------------------------+--------------------------------------------------------------+----------------+---------------------+---------------------+
5|  2 | admin | youyou@youyou.co.jp | $2y$10$vrbkT1/qXbLCGTEz/96IYO9hM1Xijle7vMuIFAUD6fqDkJl5wP0Ny | NULL           | 2018-07-20 19:56:38 | 2018-07-20 19:56:38 |
6+----+-------+-------------------------+--------------------------------------------------------------+----------------+---------------------+---------------------+
7

こちらがmysqlの環境構築に使ったファイルです。
名前はmysqlで作っています。

# docker-compose.yml(mysql)

version: '3'
services:
  mysql:
    image: mysql:5.7
    container_name: mysql5.7
    ports:
      - 3306:3306
    environment:
      - "MYSQL_ALLOW_EMPTY_PASSWORD=yes"
    restart: always

  phpmyadmin:
      image: phpmyadmin/phpmyadmin
      container_name: phpmyadmin
      environment:
        - PMA_HOST=mysql
        - PMA_PORT=3306
        - PMA_USER=root
      ports:
        - 8081:80

networks:
  default:
    external:
      name: common_link

Laravelの.env
こちらのDB_HOSTをdocker-compose.ymlのmysqlの名前に設定

APP_NAME=Laravel
APP_ENV=local
APP_KEY=C0PKuch0a0W2z9kKLufQZJ8VQ=
APP_DEBUG=true
APP_URL=http://cms.local.jp

LOG_CHANNEL=stack

DB_CONNECTION=mysql
DB_HOST=mysql
DB_PORT=3306
DB_DATABASE=cms
DB_USERNAME=root
DB_PASSWORD=

BROADCAST_DRIVER=log
CACHE_DRIVER=file
SESSION_DRIVER=file
SESSION_LIFETIME=120
QUEUE_DRIVER=sync

REDIS_HOST=127.0.0.1
REDIS_PASSWORD=null
REDIS_PORT=6379

MAIL_DRIVER=smtp
MAIL_HOST=smtp.mailtrap.io
MAIL_PORT=2525
MAIL_USERNAME=null
MAIL_PASSWORD=null
MAIL_ENCRYPTION=null

PUSHER_APP_ID=
PUSHER_APP_KEY=
PUSHER_APP_SECRET=
PUSHER_APP_CLUSTER=mt1

MIX_PUSHER_APP_KEY="${PUSHER_APP_KEY}"
MIX_PUSHER_APP_CLUSTER="${PUSHER_APP_CLUSTER}"

Laravelプロジェクトの入っているコンテナのDcokerfileとdocker-compose.yml

version: '3'
services:
  web:
    build:
      context: "./"
      dockerfile: ./Dockerfile
    container_name: "cms"
    command: "/sbin/init"
    volumes:
      - ./html:/var/www/html
      - ./nginx/conf.d:/etc/nginx/conf.d/
      - ./php/php.ini:/etc/php.ini
      - ./php-fpm/www.conf:/etc/php-fpm.d/www.conf
      - ./supervisor/supervisord.conf:/etc/supervisord.conf
      - /Users/user/dev/cms:/var/www/
    ports:
      - 90:80
    environment:
      - VIRTUAL_HOST=cms.local.jp
    tty: true

networks:
  default:
    external:
      name: common_link

FROM amazonlinux:1


RUN rpm --import http://rpms.famillecollet.com/RPM-GPG-KEY-remi &&\
    rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm && \
    rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm

RUN yum update -y

RUN yum install -y \
    initscripts \
    sudo \
    git \
    zip \
    unzip \
    nginx --skip-broken \
    httpd \
    wget \
    less \
    libxslt \
    automake \
    autoconf \
    mysql \
    libmcrypt \
    libtool-ltdl \
    gcc gcc-c++

# TODO: supervisorのインストール
# コンテナの構築後に supervisord コマンドを実行してプロセスを起動させる
# RUN yum install -y python27-setuptools.noarch &&\
#    easy_install pip &&\
#    pip install supervisor --install-option="--install-scripts=/usr/bin"

RUN yum install -y --disablerepo=amzn-main,amzn-updates --enablerepo=remi,remi-php71 \
    php php-devel php-common php-mbstring php-pdo php-xml php-fpm php-mysql php-soap php-mcrypt

RUN touch /etc/sysconfig/network

RUN useradd docker

RUN service nginx start &&\
    service php-fpm start &&\
    service iptables stop

RUN chkconfig nginx on &&\
    chkconfig php-fpm on &&\
    chkconfig iptables off

RUN chown -R root:nginx /var/log/nginx

RUN chmod -R 770 /var/log/nginx/

CMD ["nginx", "-g", "daemon off;"]