General adjustments

I updated the meme show page to only show edit/delete options for the author of the meme. Also updated the ER picture to be more accurate. Added in the older devise tests I had deleted off master. This way we should be able to keep the old tests we wrote and not have merge conflicts when merging in the carrierwave branch.
I would skip this step and just create a user directly with FactoryGirl:

```ruby
user = FactoryGirl.create(:user)
```