Add a base URL to the template context, fix the notmyidea theme to be a bit more

prettier.

samples/themes/notmyidea/templates/categories.html

@@ -0,0 +1,8 @@
+{% extends "base.html" %}
+{% block content %}
+<ul>
+{% for category, articles in categories %}
+    <li>{{ category }}</li>
+{% endfor %}
+</ul>
+{% endblock %}