added validations to response model (presence of notice_id, user_id, uniqueness of user_id on notice_id)
no acceptance test w/ guard
Merge pull request #396 from DonutWorks/feature/issue-395

added validations to response model (presence of notice_id, user_id, uni...
Merge pull request #400 from DonutWorks/feature/issue-398

no acceptance test w/ guard
Merge branch 'develop' of github.com:DonutWorks/Ari into feature/design-follow-develop