Source: https://github.com/allenporter/supernote
Give the directory permission:
mkdir -p /srv/docker/supernote/
chown -R 1000:1000 /srv/docker/supernote
Once the server is running, register your administrator account:
Using Docker CLI:
# Create the initial admin account
docker exec -it supernote supernote admin --url http://localhost:8000 user add you@example.com