Automatically set a forum slug based on name if it's not provided

Forum solr tests require this field

forum/models.py

@@ -37,6 +37,7 @@
 from utils.cache import invalidate_template_cache
 from utils.search import SearchEngineException, get_search_engine
 from utils.search.search_forum import delete_posts_from_search_engine
+from utils.text import slugify
 
 web_logger = logging.getLogger('web')
 
@@ -76,6 +77,14 @@ def get_absolute_url(self):
         return reverse("forums-forum", args=[smart_unicode(self.name_slug)])
 
 
+@receiver(pre_save, sender=Forum)
+def forum_pre_save_set_slug(sender, instance, **kwargs):
+    """If a forum has a name set but not a slug, automatically generate the slug
+    """
+    if not instance.id and not instance.name_slug:
+        instance.name_slug = slugify(instance.name)
+
+
 class Thread(models.Model):
     forum = models.ForeignKey(Forum)
     author = models.ForeignKey(User)