Expire special m- and c- reply addresses after a month

script/deliver-message

@@ -7,16 +7,19 @@ exit 0 unless recipient = ARGV[0].match(/^([cm])-(\d+)-(.*)$/)
 if recipient[1] == "c"
   comment = DiaryComment.find(recipient[2])
   digest = comment.digest
+  date = diary_comment.created_at
   from = comment.diary_entry.user
   to = comment.user
 else
   message = Message.find(recipient[2])
   digest = message.digest
+  date = message.sent_on
   from = message.recipient
   to = message.sender
 end
 
 exit 0 unless recipient[3] == digest[0,6]
+exit 0 if date < 1.month.ago
 
 message.update_attribute(:message_read, true) if message