add missing quotes

content/en_index.php

diff --git a/content/en_index.php b/content/en_index.php
index 601e706..4e017ce 100644
--- a/content/en_index.php
+++ b/content/en_index.php
@@ -38,7 +38,7 @@
 	If you would like to know more, the DAWN project has an active mailing
 	list which is open to subscribers Jiscmail Mailing list. Alternatively
 	you could follow us on Twitter. Dawn is open source and available on
-	<a href=https://github.com/dawnscience>GitHub</a>.
+	<a href="https://github.com/dawnscience">GitHub</a>.
 	</p>
 	<div class="news-list">
 		<h2>