docker-compose exec app bash
root@1d494784f8e6:/data# composer install
root@1d494784f8e6:/data# npm install
root@1d494784f8e6:/data# npm run build
root@1d494784f8e6:/data# cp .env.example .env
root@1d494784f8e6:/data# php artisan key:generate
INFO Application key set successfully.
もしPermissionDenied!と言われたら?
$ php artisan cache:clear
$ php artisan route:clear
$ php artisan config:clear
キャッシュクリアをしたら治る 参考リンク:https://qiita.com/phper_sugiyama/items/ae308c2a61aa3dbc3bf3