Add travis file for CI

1. Build the .html files through Docker + Make
2. Only triggered by changes on develop branch
3. Pushed results to master branch

Author: ryukinix

.travis.yml

@@ -0,0 +1,14 @@
+# ref: https://docs.travis-ci.com/user/deployment/pages/
+
+services:
+  - docker
+
+script: make
+
+deploy:
+  provider: pages
+  skip-cleanup: true
+  keep-history: true
+  on:
+    branch: develop
+  target-branch: master