Link to Git repository in header

templates/index.html

@@ -13,7 +13,9 @@
 		<div class="wrap">
 			<a href="{{ config.base_url }}" class="title">{{ config.title }}</a>
 			<nav>
-				<a href="">Source</a>,
+				{% if config.extra.repository_url %}
+					<a href="{{ config.extra.repository_url }}">Source</a>,
+				{% endif %}
 				<a href="{{ get_url(path="/posts/atom.xml", trailing_slash=false) }}">RSS/Atom</a>
 			</nav>
 		</div>