Added PageSpeed Insights in performance section

README.md

@@ -323,6 +323,7 @@ Before add pull request please see **[this](https://github.com/trimstray/the-boo
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://performance.sucuri.net/"><b>Sucuri loadtimetester</b></a> - test here the
 performance of any of your sites from across the globe.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://tools.pingdom.com/"><b>Pingdom Tools</b></a> - analyze your site’s speed around the world.<br>
+&nbsp;&nbsp;:small_orange_diamond: <a href="https://developers.google.com/speed/pagespeed/insights/"><b>PageSpeed Insights</b></a> - analyze your site’s speed and make it faster.<br>
 </p>
 
 ##### :black_small_square: Mass scanners (search engines)