Add simple date, tags to posts.

static/article.tmpl.html

@@ -29,7 +29,19 @@
       <div class="content">
         <article class="post">
           <h2 class="post-title">{{ title }}</h2>
-          {{ content | safe }}
+          <div class="post-metadata">
+            <time datetime="{{ post_publication_date }}">
+              {{ post_publication_date }}
+            </time>
+            <ul class="post-tags">
+              {% for post_tag in post_tags %}
+              <li class="post-tag">{{ post_tag }}</li>
+              {% endfor %}
+            </ul>
+          </div>
+          <div class="post-content">
+            {{ content | safe }}
+          </div>
         </article>
       </div>
     </body>