ReactN devtool
https://github.com/CharlesStover/reactn-devtools#readme
https://github.com/reduxjs/redux-devtools
$ npm install redux
$ npm install reactn-devtools
https://gyazo.com/bfc2e482c5f14bb18de0c695a27c6752
https://gyazo.com/04129f9cb2c1de8e71411bcc5f546078