(defun add-attribution ()
  (interactive)
  (save-excursion
    (let ((start-id (point))
	  (attribution-username (user-login-name (user-uid)))
	  (attribution-prefix "")
	  (attribution-suffix ":  ")
	  (attribution (concat attribution-username
			       attribution-prefix
			       attribution-suffix)))
      (insert attribution)
      (setq attribution-end-point (point))
      (comment-region start-id (point))))
  (goto attribution-end-point))