[UPD] addons table in README.md

README.md

@@ -13,6 +13,7 @@ Available addons
 addon | version | summary
 --- | --- | ---
 [email_template_qweb](email_template_qweb/) | 9.0.1.0.0 | Use the QWeb templating mechanism for emails
+[mail_as_letter](mail_as_letter/) | 9.0.1.0.0 | This module allows to download a mail message as a pdf letter.
 [mail_attach_existing_attachment](mail_attach_existing_attachment/) | 9.0.1.0.0 | Adding attachment on the object by sending this one
 [mail_optional_autofollow](mail_optional_autofollow/) | 9.0.1.0.0 | Choose if you want to automatically add new recipients as followers on mail.compose.message