MessageBuilder.md in mailgun-ruby-1.1.8

- old
+ new

@@ -42,9 +42,12 @@
 
 # Or clear the Message-Id header, provide nil or empty string.
 mb_obj.message_id(nil)
 mb_obj.message_id('')
 
+# Set the Message-tags at most 3.
+mb_obj.add_tag("You can track mails as tag-units!")
+
 # Campaigns and headers.
 mb_obj.add_campaign_id("My-Awesome-Campaign");
 mb_obj.header("Customer-Id", "12345");
 
 # Custom variables