build --prod on travis

Author: mpalourdio

.travis.yml

@@ -19,7 +19,7 @@ script:
   - yarn lint
   - yarn audit
   - yarn test --code-coverage
-  - yarn build
+  - yarn build --prod
 
 after_script:
   - cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js