Currently any user can edit any task raised in the system, changing the task's due date, description or assignee.
Ideally, a task should be editable only by the person who raised it initially (or, alternatively, by a user with a specific permission).
The main inconveniences with the current setup are:
- a user can push the due date forever - instead of completing the task, push it forward so that it doesn't show as overdue
- a user can change an important note in the task - for example, remove someone else's text