diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -32,6 +32,7 @@ translationstring==1.3
 webob==1.8.4
 zope.deprecation==4.3.0
 zope.interface==4.5.0
+venusian==1.2.0
 
 ## http servers
 gevent==1.3.7