Add option to display rss feed link in navigation menu

layouts/partials/nav-bar.html

@@ -19,7 +19,7 @@
       {{ range $key, $value := .Site.Taxonomies.categories -}}
       <li><a href="{{ (printf "%s%s" "categories/" ($key | urlize)) | absURL }}" class="hamburger-menu-overlay-link">{{ $key | humanize }}</a></li>
       {{- end }}
-      {{ if isset $.Site.Params "rssinmenu" -}}
+      {{ if eq .Site.Params.rssinmenu true -}}
       <li><a href="{{ "/index.xml" | absURL }}" class="hamburger-menu-overlay-link">rss</a></li>
       {{- end }}
     </ul>