site logo is a link

layouts/partials/header.html

@@ -1,6 +1,6 @@
 <div>
 {{ with resources.Get site.Params.logo.src }}
-  <img src="{{ .RelPermalink }}" width="{{ .Width }}" height="{{ .Height }}" alt="{{ site.Params.logo.alt }}">
+  <a href="/"><img src="{{ .RelPermalink }}" width="{{ .Width }}" height="{{ .Height }}" alt="{{ site.Params.logo.alt }}"></a>
 {{ else }}
   <h1>{{ site.Title }}</h1>
 {{ end }}