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.
You don't need to test every possible scenario here. You can assume that Devise will handle a lot of these validations and that the `devise` gem has been thoroughly tested. What you really want to test is that the edit account feature is properly integrated into your app and that it sends users to the right place when everything goes smoothly (user enters the correct password) and when it fails (e.g. some validation failed). So I would cut this back to 2 tests.