A "UserBlocked" table [exists](https://github.com/CheapReaders/Readr/blob/876cc021e8de232d3ab2a0419c075b3bccf211b1/sequelize/index.js#L71) in the database. We need routes creacted and helper functions (if needed). A "block" button should be added [under each follower on "Follower List" view](https://github.com/CheapReaders/Readr/blob/876cc021e8de232d3ab2a0419c075b3bccf211b1/client/src/components/UserFollower.jsx#L45)