Merge pull request #105 from DanySK/fix_ci

Fix the continuous integration (supersedes previous PR)

.travis.yml

@@ -1,9 +1,6 @@
 language: ruby
-rvm:
+script:
-- 2.3.3
+  - gem install jekyll bundler
-
+  - bundle install
-install: gem install jekyll
+  - bundle exec jekyll build
-script: jekyll build
+cache: bundler
-
-sudo: false
-exclude: [vendor]