From f918d3e89b7421be112529e54caedcdda433b88b Mon Sep 17 00:00:00 2001
From: Jeff Atwood <jatwood@codinghorror.com>
Date: Wed, 26 Nov 2014 16:35:56 -0800
Subject: [PATCH] FEATURE: add Message-ID header to emails

when topic present for email of course
---
 lib/email/sender.rb | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/email/sender.rb b/lib/email/sender.rb
index 8fcbd1c5f14..19319b1d77a 100644
--- a/lib/email/sender.rb
+++ b/lib/email/sender.rb
@@ -67,6 +67,8 @@ module Email
         email_log.topic_id = topic_id
 
         topic_identifier = "<topic/#{topic_id}@#{host}>"
+        post_identifier = "<topic/#{topic_id}/#{post_id}@#{host}>"
+        @message.header['Message-ID'] = post_identifier
         @message.header['In-Reply-To'] = topic_identifier
         @message.header['References'] = topic_identifier