newer version of separating upcoming activities mendicant#19

activities.markdown

@@ -8,7 +8,22 @@ header:
 ---
 
 <ul class="posts">
+{% assign past_header_shown = false %}
 {% for post in site.categories.activities %}
+  {% unless post.next %}
+    {% if site.time < post.date %}
+      <h2>upcoming</h2>
+    {% else %}
+      <h2>past</h2>
+      {% assign past_header_shown = true %}
+    {% endif %}
+  {% else %}
+    {% if site.time >= post.date and past_header_shown == false %}
+      <h2>past</h2>
+      {% assign past_header_shown = true %}
+    {% endif %}
+  {% endunless %}
+
   {% include post.html %}
 {% endfor %}
 </ul>