Handle application/ms-tnef; as an attachment

ruby-dev: 1148

Author: amatsuda

app/models/message.rb

@@ -72,6 +72,9 @@ def from_mail(mail, list, list_seq)
       attachments.attach(io: file, filename: part.filename, content_type: part.content_type)
     else
       case part.content_type.downcase
+      when 'application/ms-tnef'
+        file = StringIO.new(part.decoded)
+        attachments.attach(io: file, filename: part.filename || 'noname', content_type: part.content_type)
       when /^text\/plain/, /text\/enriched;/
         (self.body ||= '') << Kconv.toutf8(part.body.raw_source)
       when /^text\/html;/