Add handling for bounce mails

app/mail_receivers/bounce_mail_receiver.rb

@@ -0,0 +1,17 @@
+class BounceMailReceiver
+
+  def self.regexp
+    /bounce\+(?<local>.*)=(?<domain>[^=]+)/
+  end
+
+  def received(match, data)
+    address = "#{match[:local]}@#{match[:domain]}"
+    mail = Mail.new data
+    subject = mail.subject || 'Unknown bounce error'
+    MailDeliveryStatus.create email: address,
+                              message: subject,
+                              attachment_mime: 'message/rfc822',
+                              attachment_data: data
+  end
+
+end