Add base_url option

_config.yml

@@ -1,3 +1,3 @@
 title: Pico
 description: A stupidly simple, blazing fast, flat file CMS.
-
+base_url: http://phrozenbyte.github.io/Pico/

_includes/pageHeader.html

@@ -8,7 +8,7 @@
                 {% for nav in pages %}
                     {% if nav.nav > 0 %}
                         <li {% if nav.url == page.url %}class="active"{% endif %}>
-                            <a href="{{ nav.url }}">{{ nav.title }}</a>
+                            <a href="{{ site.base_url }}{{ nav.url }}">{{ nav.title }}</a>
                         </li>
                     {% endif %}
                 {% endfor %}