Update single to work as a main block

layouts/_default/single.html

@@ -1,3 +1,5 @@
+{{ define "main" }}
+
 {{ partial "header.html" . }}
 
 {{ partial "navigation.html" . }}
@@ -22,4 +24,4 @@
     </div>
 </section>
 
-{{ partial "footer.html" . }}
+{{ end }}