diff --git a/requirements.txt b/requirements.txt
index 8c2d4e91..74438405 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,3 +5,5 @@ jupyterhub>=1.2
 requests
 # ruamel.yaml is used to read and write .yaml files.
 ruamel.yaml
+tornado
+traitlets