User Story 22, (EXTENSION 2/4) Review usernames are unique for a given book #3
Description
As a Visitor,
I should not be permitted to save a book review using a name
I've previously used to review a specific book.
(user names are unique for a specific book's reviews)
Checklist:
- base code tests are written
- base code is written to pass tests
- edge case ("sad path") tests written
- edge case code written
- code is reviewed
- branch is merged
- all tests still pass
child of #5
child of #33
depends on #16