1. When you meet "can't resolve 'redux' 1493?? error, the console window says run three commands blah blah. 'watchman watch-del-all' for instance.
2. You could follow the direction first or last
3. Make sure you install redux and react-redux package.

$ npm i --save redux
$ npm i --save react-redux
$ npm install

Darn, once I read the error message and the instruction, I thought that it was cache or similar problem. However, its root cause was not even close to that!! Don't forget this.
Even though it is very simple one, it is worth to remember at this point.