Add by-line, even though still not being rendered.

layouts/_default/single.html

@@ -16,6 +16,9 @@
             {{ if .Params.subtitle }}
             <strong>{{ .Params.subtitle | markdownify }}</strong>
             {{ end }}
+            {{ if .Params.author }}
+            <pre>by {{ .Params.author }}</pre>
+            {{ end }}
 
             {{ if .Params.Cover }}
                 <figure class="post-cover">