We use a gem package for solving door_3. We have tried to add multitple languages in build so we can run our gem package and pass our test.

.travis.yml

@@ -1,10 +1,19 @@
-language: python
+matrix:
-python:
+  include:
+    - language: ruby
+      rvm:
+        - 2.2
+        - jruby
+        - 2.0.0-p247
+      install: gem install zsteg
+
+    - language: python
+      python:
         - 3.6
-install:
+      install:
         - pip install -r requirements.txt
-script:
+      script:
         - pytest --junitxml=result.xml
         - python badge.py
-after_success:
+      after_success:
         - coveralls