title: error 'document' is not defined : eslint / React
body: <p>I'm building a React app, with create-react-app.</p>
  
  <p>I got the following error when running ESLint:<br>
  <code>8:3  error  'document' is not defined  no-undef.</code></p>
  
  <p>My app runs without error, but I got this ESLint error in 2 files.
  See one of those <code>.jsx</code> files and my ESLint configuration.</p>
  
  <p>index.jsx:</p>
  
  <pre><code>import React from 'react';
  import ReactDOM from 'react-dom';
  import App from './App';
  import './index.css';
  
  ReactDOM.render(
    &lt;App /&gt;,
    document.getElementById('root'),
  );
  </code></pre>
  
  <p>eslintrc.js:</p>
  
  <pre><code>module.exports = {
    "extends": "airbnb",
    "plugins": [
        "react",
        "jsx-a11y",
        "import"
    ],
    "env": {
      "jest": true
    }
  };
  </code></pre>
  
  <p>How can I fix this ? For the moment I will simply ignore both files ... but I'd rather find a long term solution.</p>