refactor follow, unfollow, shout, unshout to custom mutations, but don't add date-time to relation yet

Created by: Tirokk

Authored by Tirokk Apr 11, 2019 Merged Apr 17, 2019

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Together with @mattwr18 . 😄

Pullrequest

Issues

• relates #219 (closed)
• Customises mutations follow, unfollow, shout, unshout.
• Add date-time to relation.

How2Test

• $ docker-compose exec backend yarn test:jest backend/src/resolvers/follow.spec.js backend/src/resolvers/shout.spec.js