preinstall apt https transport
diff --git a/.travis.yml b/.travis.yml
index 2a33688..9ab7afc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,11 @@
 services:
   - docker
 
+addons:
+  apt:
+    packages:
+    - apt-transport-https
+
 install:
   - pip install PyYAML
   - pip install virtualenv