Adds index template

It shows only articles' titles in a bulleted list, sorted in ascending alphabetical order.
It doesn't show article's summary, publication date and other stuff.

templates/index.html

@@ -0,0 +1,9 @@
+{% extends "!simple/index.html" %}
+
+{% block content %}
+<h2>All articles</h2>
+       {% for article in articles | sort(attribute='title') %}
+        <li><a href="{{ SITEURL }}/{{ article.url }}">{{ article.title }}</a></li>
+       {% endfor %}
+       {% include 'pagination.html' %}
+{% endblock content %}