Don't do anything before confirmation

[lolmaus]

When I run an ember release command with arguments, I see this:

$ ember release --premajor alpha
Successfully committed changes 'Released v0.1.0' locally.
? About to create tag 'v0.1.0' and push to remote 'origin', proceed?

I notice a mistake and cancel. But commit has already been made!

Why? ember-cli-release is pretty unintiutive, so mistakes are common. I want to be able to confirm/cancel before it makes any actual changes.