Added missing filters

smash/web/templatetags/__init__.py

+#

smash/web/templatetags/filters.py

+# See: http://stackoverflow.com/a/18962481
+from django import template
+
+register = template.Library()
+
+@register.filter(name='add_class')
+def add_class(value, arg):
+    css_classes = value.field.widget.attrs.get('class', ' ').split(' ')
+    if css_classes and arg not in css_classes:
+        css_classes = '%s %s' % (css_classes, arg)
+    return value.as_widget(attrs={'class': css_classes})
+
+@register.filter(name='disable')
+def disable(value):
+    value.field.widget.attrs['disabled']='disabled'
+    return value