Default cache_store is FileStore according to [RailsGuide](http://guides.rubyonrails.org/caching_with_rails.html#activesupport-cache-filestore). Maybe setting this to MemoryStore would be better for our largely-static model classes? (also: I'm new to Rails, I don't know if this is at all an improvement over caching via class-variable storage, or if we should just leave this stuff as it was)