metrunome is invite-only
Sorry — you got all the way through the Spotify prompt and there's nothing on the other side of it. That's this project's fault, not yours.
Why
Spotify allows an app like this five people, added by hand. Lifting that limit needs a registered company with a quarter of a million monthly users, which metrunome — one person, evenings — is never going to be. So the five slots are permanent, and they're taken.
Spotify lets you authorise an app before checking whether it's allowed to have you, which is why you were asked for permission at all. It shouldn't have got that far.
Nothing was created
No account, no data, nothing stored. The only trace is the permission you just granted, and you can take it back at spotify.com/account/apps — worth doing, since it's no use to you now.
If you know Ben
Ask, and if a slot is free it takes a minute to add you. Otherwise: contact@metrunome.com.