Add to changelog.

CHANGELOG

-v6.7.2
+v 6.8.0
+  - Ability to at mention users that are participating in issue and merge req. discussion
+
+v 6.7.2
   - Fix upgrader script
-v6.7.1
+v 6.7.1
   - Fix GitLab CI integration
 v 6.7.0

lib/gitlab/markdown.rb

@@ -167,7 +167,7 @@ module Gitlab
     def reference_user(identifier)
       if user = User.find_by_username(identifier)
-        link_to("@#{identifier}", user_url(identifier), html_options.merge(class: "gfm gfm-team_member #{html_options[:class]}")) if user
+        link_to("@#{identifier}", user_url(identifier), html_options.merge(class: "gfm gfm-team_member #{html_options[:class]}"))
       end
     end