Add a section in the footer to denote that the article is pinned.

layouts/posts/single.html

@@ -67,6 +67,11 @@
     <hr />
 
     <div class="post-info">
+      {{ if .Params.pinned }}
+      <img style="display: inline-block; vertical-align: middle; margin-right: 4px;"
+          src="/feathericons/16px-a9a9b3/paperclip.svg" alt="Pinned:"
+      > <a href="/categories/pinned">This article is pinned.</a>
+      {{ end }}
       {{ partial "tags.html" . }}
       {{ partial "series.html" . }}
       {{ partial "categories.html" . }}