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.
This should be `==` rather than `=`. Otherwise it will always return true as long as there is a user signed in.