Quick start:
$ yarn # npm install
$ yarn build # npm run build
$ npm start
errors at npm start
https://stackoverflow.com/questions/31976722/start-script-missing-error-when-running-npm-start
https://exerror.com/fix-the-upstream-dependency-conflict-installing-npm-packages/
> start
> react-scripts --openssl-legacy-provider start
'react-scripts' is not recognized as an internal or external command,
operable program or batch file.
try type npm install react-scripts --save