Point project submissions to forum.

index.html

@@ -288,7 +288,7 @@
 		<div id="viewer">
 
 			<h2>featured projects</h2>
-			<a id="submit" href="https://docs.google.com/forms/d/e/1FAIpQLSfrfc5cKz5HlWOYuYKP4igo0U0iUNtacfIwM54WEYXReJOO2Q/viewform">submit project</a>
+			<a id="submit" href="https://discourse.threejs.org/c/showcase">submit project</a>
 
 			<div id="projects">