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 :)
Our model for CoverPhoto -- if we really wanted we could make this even more generic by calling it Photo, and then we could attach it to any model we wanted and get photos! All you'd have to do would be say:

```has_many :photos```

And bam, you have paper_clip attachable images for slideshows, etc. No need to add paperclip to every single model that might have uploads!