Epic : user can delete profile

[RachWalm]

Story

As a Volunteer, I can delete my profile so that I can stop using the site and stop them having access to my details.

Acceptance Criteria

• Profile delete function works

Tasks

• [x] Set up a profile delete function
• [x] Have the delete function remind the volunteer that this can't be undone
• [x] Test function

[RachWalm]

See stories #89 and #40