Enable mattermost profile verification

themes/sustain/layouts/partials/social.html

@@ -5,7 +5,7 @@
     {{ with .Site.Social.linkedin }}<a href="https://linkedin.com/in/{{.}}"><i class="fa fa-linkedin"></i></a>{{ end }}
     {{ with .Site.Social.googlescholar }}<a href="https://scholar.google.com/citations?user={{.}}"><i class="fa fa-graduation-cap"></i></a>{{ end }}
     {{ with .Site.Social.twitter }}<a href="https://twitter.com/{{.}}"><i class="fa fa-twitter"></i></a>{{ end }}
-    {{ with .Site.Social.mastodon }}<a href="{{.}}"><i class="fa fa-paw"></i></a>{{ end }}
+    {{ with .Site.Social.mastodon }}<a rel="me" href="{{.}}"><i class="fa fa-paw"></i></a>{{ end }}
     {{ with .Site.Social.keybase }}<a href="https://keybase.io/{{.}}"><i class="fa fa-key"></i></a>{{ end }}
     {{ with .Site.Social.email }}<a href="mailto:{{.}}"><i class="fa fa-envelope"></i></a>{{ end }}
   </h4>