Add broken-link-checker.

Author: XhmikosR

.travis.yml

@@ -13,6 +13,9 @@ before_install:
 install:
   - bundle install --deployment --jobs=3 --retry=3
   - npm install
+script:
+  - npm test
+  - if [ "$TRAVIS_NODE_VERSION" = "8" ]; then npm run check-broken-links; fi
 after_success:
   - if [ "$TRAVIS_NODE_VERSION" = "8" ]; then npm run coveralls; fi
 stages: