add three-seed link to docs

docs/manual/introduction/Useful-links.html

@@ -91,6 +91,9 @@
 
 		<h2>Examples</h2>
 		<ul>
+			<li>
+				[link:https://github.com/edwinwebb/three-seed/ three-seed] - three.js starter project with ES6 and Webpack
+			</li>
 			<li>
 				[link:http://stemkoski.github.io/Three.js/index.html Professor Stemkoskis Examples] - a collection of beginner friendly
 				examples built using three.js r60.