1👍
Found your problem when I looked a bit further into your library.
From the Johnny Cache documentation:
It works with Django 1.1 thru 1.4 and python 2.4 thru 2.7.
From your question:
I’m migrating my project to Django 1.8.
In fact, it looks like the library you’re using is woefully out of date and no longer maintained:
Latest commit d96ea94 on Nov 10, 2014
Source:stackexchange.com