enable react in scope lint rule

.eslintrc.js

@@ -15,7 +15,6 @@ module.exports = {
   },
   plugins: ['react', 'import'],
   rules: {
-    'react/react-in-jsx-scope': 'off',
     'react/prop-types': 'off',
     'react/display-name': 'off',
     'react/jsx-uses-react': 'error',

components/Meta.js

@@ -1,3 +1,4 @@
+import React from 'react'
 import Head from 'next/head'
 import { THEMES, THEMES_HASH } from '../lib/constants'
 import Reset from './style/Reset'

components/Overlay.js

@@ -1,3 +1,5 @@
+import React from 'react'
+
 const Overlay = props => (
   <div className="dnd-container">
     {props.isOver ? <div className="dnd-overlay">{props.title}</div> : null}

pages/_document.js

@@ -1,3 +1,4 @@
+import React from 'react'
 import Document, { Head, Main, NextScript } from 'next/document'
 
 export default class extends Document {

pages/about.js

@@ -1,3 +1,4 @@
+import React from 'react'
 import Page from '../components/Page'
 import { COLORS } from '../lib/constants'