add: show last updated date on detail top bar

browser/main/Detail/LastUpdatedString.js

@@ -0,0 +1,27 @@
+/**
+ * @fileoverview Component for show updated date of the detail.
+ */
+import React, { PropTypes } from 'react'
+import { getLastUpdated } from 'browser/lib/date-formatter'
+import CSSModules from 'browser/lib/CSSModules'
+import styles from './LastUpdatedString.styl'
+
+const LastUpdatedString = ({ date }) => {
+  let text = ''
+
+  try {
+    text = `Last updated at ${getLastUpdated(date)}`
+  } catch (e) {
+    text = ''
+  }
+
+  return (
+    <p styleName='info-right-date'>{text}</p>
+  )
+}
+
+LastUpdatedString.propTypes = {
+  date: PropTypes.string,
+}
+
+export default CSSModules(LastUpdatedString, styles)