Remove 'Powered by Ghost'

Hey.

I've been trying out Ghost and while it's really good, it seems "Powered by Ghost" text on Footer is forced. It's quite easily removed on WordPress (and many themes have easy option to remove it), but I did not find the option on Ghost.

How can we remove the "Powered by Ghost"?

I am using the theme 'Headline,' if that matters.

Thank you.