diff --git a/.travis.yml b/.travis.yml
index 7ef0ca5..2e0a6cf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,9 @@
 sudo: required
 
+before_install:
+  - sudo apt-get -qq update
+  - sudo apt-get install -y tree
+
 services:
   - docker