Yeah, I'm sorry about that. I'm starting to look into a native iOS app, but it's going to be a little while. In the meantime, I think Apple did mention something about progressive web apps last week at WWDC -- I'll have to look that up.
Now that you mention it, I'll have to re-think -- with the Google option there as the "easy" route, maybe username & password is a better backup option because it's more universal.