Add atom/rss/json feeds

src/blog/index.html

@@ -13,7 +13,7 @@ pagination:
         {% for item in pagination.items %}
         <li class="stack-xs">
             <h2><a href="{{ item.url }}">{{ item.data.title | safe }}</a></h2>
-            <time class="block" datetime="{{ item.date | rfc3339 }}">{{ item.date | dateDisplay }}</time>
+            <time class="block" datetime="{{ item.date | dateToRfc3339 }}">{{ item.date | dateDisplay }}</time>
             <div class="e-content p-summary">{{ item.content | excerpt }}</div>
             <a href="{{ item.url }}" class="inline-block">Read more</a>
         </li>