Because Giftless uses signed URLs, this is a bit more complex than the initial cut.

It's working now (at least for me). Because the app is still pinned to Python 3.7, which is increasingly difficult to develop for (especially on an ARM Mac), I haven't even tried to update test cases, which would require updating test case cassettes, which drags me right into dependency hell.

The good news is, flask-classful finally got an update to 0.16 (and a new maintainer) so it might now be possible to rebuild the whole app with modern versions of packages and get to a current Python version. That will be a separate PR if my management approves my spending the effort to do so.

Addresses #108

Fantastic, please merge @athornton

@athornton thank-you so much and we'd welcome upgrade to later python versions if you were up for it!.

LGTM and merging here.