That's definitely something we'd want to add. At the moment we wanted to release an MVP and see if people like it before adding accounts and other features. We didn't think it was crucial to getting the core experience with the product, but we're going to keep improving it over time. For now, you could save locally or to Dropbox to avoid losing revisions. Thank you for the comment, I'd recommend signing up to the mailing list to hear about when things like accounts would launch.