Invite reviewer¶

As a reviewer
I can invite other people to the group 'reviewers'
so my colleaguese can review questionnaires as well.

Acceptance criteria¶

• Reviewers can invite other people, this triggers a mail.
• If the person already has a wocat user, the permissions for 'review' are granted, and a mail is sent to the person
• If the person doesn't have a wocat account, the person receives an email with the link to the registration and a link to click once the registration is finished. * When clicking the additional link, a unique url is called which then adds the permissions to review for given user. * If the link is clicked, but the user doesn't exist yet, an error message is displayed.