MediaGoblin currently uses SQLAlchemy < 1.4, but Guix recently upgraded to 1.4, so to support Guix we either need to re-introduce 1.3 or upgrade MediaGoblin to 1.4.

Debian Sid currently has 1.4 and Debian Testing has 1.3. Since our deployment docs use a virtualenv, that's mostly not an issue though, since the correct version will be fetched from PyPI.