add React & Redux devtools

browser/main/DevTools/index.dev.js

@@ -0,0 +1,16 @@
+import React from 'react'
+import { createDevTools } from 'redux-devtools'
+import LogMonitor from 'redux-devtools-log-monitor'
+import DockMonitor from 'redux-devtools-dock-monitor'
+
+const DevTools = createDevTools(
+  <DockMonitor
+    toggleVisibilityKey='ctrl-h'
+    changePositionKey='ctrl-q'
+    defaultIsVisible={false}
+  >
+    <LogMonitor theme='tomorrow' />
+  </DockMonitor>
+)
+
+export default DevTools

browser/main/DevTools/index.js

@@ -0,0 +1,8 @@
+/* eslint-disable no-undef */
+if (process.env.NODE_ENV === 'production') {
+  // eslint-disable-next-line global-require
+  module.exports = require('./index.prod').default
+} else {
+  // eslint-disable-next-line global-require
+  module.exports = require('./index.dev').default
+}

browser/main/DevTools/index.prod.js

@@ -0,0 +1,6 @@
+import React from 'react'
+
+const DevTools = () => <div />
+DevTools.instrument = () => {}
+
+export default DevTools