Merge pull request #388 from arachnys/add-urlvalidator-import

Add missing URLValidator in cabotapp/views.py

URLValidator is used by `clean_runbook_link()` in the ServiceForm view.

cabot/cabotapp/views.py

@@ -11,6 +11,7 @@ from django.conf import settings
 from django.contrib.auth.decorators import login_required
 from django.contrib.auth.models import User
 from django.core.exceptions import ValidationError
+from django.core.validators import URLValidator
 from django.core.urlresolvers import reverse
 from django.core.urlresolvers import reverse_lazy
 from django.http import HttpResponse, HttpResponseRedirect