What version are you running?
4.0.11
What's the URL of the page this enhancement relates to, if any?

Describe the enhancement and the motivation for it.
From command line or web ui it's possible t osubmit a new review and put yourself as reviewer. You can then do the full review process as "yourself". 

When enforcing review process, the user who submit the review hsould not be able to put himself in the review user list and should not be able to review/validate/ship-it.

It would be nice to have an option to prevent this behavior to enforce peer review.

The option should be set per repository.

What operating system are you using? What browser?
Linux
Please provide any additional information below.