diff --git a/.travis.yml b/.travis.yml
index b7fec3f..c1493f1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,7 @@ python:
  - "2.6"
  - "2.7"
 before_install:
- - sudo add-apt-repository ppa:chrysn/openscad
+ - sudo add-apt-repository -y ppa:chrysn/openscad
  - sudo apt-get update -qq
 install:
  - sudo apt-get install -qq inkscape openscad