Created by: viankakrisna
Motivation: https://github.com/facebookincubator/create-react-app/issues/2398
Right now a lot of people is confused because they suddenly have service worker in production. Rather than letting people shoot their feet, i think we need to add this message to dev environment so they will know beforehand that there will be caching etc for PWA on production builds and can make the informed decision before running npm run build
screenshot of how it look in the console
