{% url %} refactoring

using command:
 find . -type f -name "*.html" -print0 | xargs -0 sed -i 's/{% url \([^" >][^ >]*\)/{% url "\1"/g'

source: http://stackoverflow.com/questions/14882491/django-release-1-5-url-requires-a-non-empty-first-argument-the-syntax-change