Add react-app to Alternatives section in README.md

[koistya]

https://github.com/kriasoft/react-app - a tool similar to create-react-app with built-in support of CSS Modules, PostCSS, Redux, Browsersync, code splitting, async chunk loading, HMR, React Hot Loader and more awesomeness ;)

Another difference, is that it suggest a proposes the following project structure in its default template:

.
├── /actions/                   # Redux actions
├── /components/                # Shared or generic UI components
│   ├── /Button/                # Button component
│   ├── /Layout/                # Website layout component
│   ├── /Link  /                # Link component to be used insted of <a>
│   └── /...                    # etc.
├── /core/                      # Core framework
│   ├── /history.js             # Handles client-side navigation
│   ├── /router.js              # Handles routing and data fetching
│   └── /store.js               # Application state manager (Redux)
├── /node_modules/              # 3rd-party libraries and utilities
├── /routes/                    # React components for application routes
│   ├── /Error/                 # Error page
│   ├── /Home/                  # Home page
│   ├── /GetStarted/            # Getting Started page
│   └── /...                    # etc.
├── /public/                    # Static files such as favicon.ico etc.
│   ├── /dist/                  # The folder for compiled output
│   ├── favicon.ico             # Application icon to be displayed in bookmarks
│   ├── robots.txt              # Instructions for search engine crawlers
│   └── /...                    # etc.
├── /test/                      # Unit and integration tests
├── /utils/                     # Utility and helper classes
│── index.ejs                   # EJS template for index.html page
│── main.js                     # React application entry point
│── package.json                # The list of project dependencies and NPM scripts
└── routes.json                 # This list of application routes

[gaearon]

Thanks!