Before running docker compose up please copy the .env.example file to .env and change the database credentials.
Those credentials will be used automatically during the build step of the mysql image.
You will have also to use the same credentials in the .env file which should be available in backend/.env which is used by laravel.
To fix file permission issues execute the following command:
docker compose run --rm php chown -R www-data:www-data /appTo link the storage execute the following command:
docker compose run --rm php ln -s -f /app/storage/app/public /app/public/storage