Add rudimentary script for generating the forum archive.

templates/threads.mustache

@@ -0,0 +1,17 @@
+{{>header}}
+<h2>{{board.name}}</h2>
+<table id="threads">
+    <tr>
+        <th>Title</th>
+        <th>Poster</th>
+        <th>Date</th>
+    </tr>
+    {{#threads}}
+    <tr>
+        <td class="thread-subject"><a href="thread-{{id_topic}}">{{subject}}</a></td>
+        <td class="thread-poster">{{poster_name}}</td>
+        <td class="thread-date">{{datetime}}</td>
+    </tr>
+    {{/threads}}
+</table>
+{{>footer}}