Add generic descriptions for templates

Fixes #8
diff --git a/templates/authors.html b/templates/authors.html
index 741fc17..f668d5e 100644
--- a/templates/authors.html
+++ b/templates/authors.html
@@ -1,6 +1,9 @@
 {% extends "base.html" %}
 {% block title %}Authors | {{ SITENAME }}{% endblock %}
 
+{% block description %}A listing of all authors on this site{% endblock %}
+
+
 {% block subheader %}
 {% include "modules/blogsubheader.html" %}
 {% endblock subheader %}