diff --git a/.travis.yml b/.travis.yml
index 58543e3..cb8066a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,8 @@
 sudo: false
+addons:
+    apt:
+      packages: 
+      - tree
 install:
   - mkdir tools && cd tools
   - pwd