Fix bug in seo_metadata

Update #15

templates/page.html

@@ -17,7 +17,7 @@
 {% endif %}
 
 {% from '_includes/seo_metadata.html' import seo_metadata with context %}
-{{ seo_metadata(article) }}
+{{ seo_metadata(page) }}
 {% endblock meta_tags_in_head %}
 
 {% block content %}