add Hugo RSS Link

layouts/_default/baseof.html

 
      <link href='{{ "dist/main.css" | absURL }}' rel='stylesheet' type="text/css" />
 
+     {{ if .RSSLink }}
+      <link href="{{ .RSSLink }}" rel="alternate" type="application/rss+xml" title="{{ .Site.Title }}" />
+      <link href="{{ .RSSLink }}" rel="feed" type="application/rss+xml" title="{{ .Site.Title }}" />
+      {{ end }}
+
       {{/* NOTE: These Hugo Internal Templates can be found starting at https://github.com/spf13/hugo/blob/master/tpl/tplimpl/template_embedded.go#L158 */}}
       {{- template "_internal/opengraph.html" . -}}
       {{- template "_internal/google_news.html" . -}}