.travis.yml in meowcop-2.2.0 vs .travis.yml in meowcop-2.3.0

@@ -4,8 +4,11 @@
   - 2.3
   - 2.4
   - 2.5
   - 2.6
 
+services:
+  - docker
+
 branches:
   only:
     - master