add commas for multiple authors

post.hbs

@@ -69,7 +69,7 @@
 
         <div class="inline-grid grid-cols-1 items-start w-auto">
             <div class="gh-post-authors text-size-1 uppercase mb-3">
-                By {{#foreach authors}}<a href="{{url}}">{{name}}</a>{{/foreach}}
+                By {{#foreach authors}}<a href="{{url}}">{{name}}{{#if @last}}{{else}},{{/if}}</a>{{/foreach}}
             </div>
             <div class="gradient-line-horizontal"></div>
         </div>