Few fixes/tweaks for the Cache app, but still a bit to go

Hey man,

Here are a few things I did to tweak the application. There's actually a few more things to do to make it more secure, but I figured I had already changed a lot of things already :)
Again, if we renamed the "CoverPhoto" model to "Photo", we could just make this now:

```has_one :cover_photo, :class_name => :photo```, or something along those lines.