Only accept correct section filters.

researchquestions/website/filters/urls.py

@@ -3,7 +3,7 @@ from django.conf.urls import patterns, include, url
 urlpatterns = patterns('website.views',
 
     #### Available filters
-    url(r'^section/(?P<section>\w+)$', 'index'),
+    url(r'^section/(?P<section>[a-zA-Z]+ {0,1}[0-9]*)$', 'index'),
     url(r'^date$', 'index', {'sort': 'date'}),
     url(r'^comments$', 'index', {'sort': 'comments'}),