-[x] user must be able to create a todo (user should get a warning if attempts to create empty todo) -[x] user must be able to to mark completed todo -[x] user must be edit a todo -[x] user must be able to delete a todo -[x] when user completes a todo, it must pop to the bottom of the list (if user double clicks by mistake, he should be able to return the todo back to uncompleted) -[x] user should be able to remove all completed todo from the list -[x] programmer should code it out.