.travis.yml in licensed-1.3.4 vs .travis.yml in licensed-1.4.0

@@ -79,7 +79,13 @@
         - "3.6"
       before_script: ./script/source-setup/pip
       script: ./script/test pip
       env: NAME="pip"
 
+    - language: ruby
+      rvm: 2.4.0
+      before_script: ./script/source-setup/git_submodule
+      script: ./script/test git_submodule
+      env: NAME="git_submodule"
+
 notifications:
   disable: true