I'm trying to create Facebook app. Yet I had trouble right after creation wizard done his work.

Changing nothing in what wizard created I've got an error:

Error
You have specified an App Domain but have not specified a valid integration URL.
secure-citadel-xxxx.herokuapp.com must be derived from one of: Site URL, Mobile
Site URL, Canvas URL, Secure Canvas URL, Page Tab URL or Secure Page Tab URL.

I googled it and found no answer at what it might be..

Adding http:// and so on doesn't make anything more than another error of domain being invalid.

Does anyone know ho to deal with it?