remove `derby` from website for now

as the hosted version is gone

https://github.com/tastejs/todomvc/issues/546

index.html

@@ -289,9 +289,6 @@
 						<li>
 							<a href="http://todomvcapp.meteor.com" data-source="http://meteor.com" data-content="Meteor is an ultra-simple environment for building modern websites. A Meteor application is a mix of JavaScript that runs inside a client web browser, JavaScript that runs on the Meteor server inside a Node.js container, and all the supporting HTML fragments, CSS rules, and static assets. Meteor automates the packaging and transmission of these different components. And, it is quite flexible about how you choose to structure those components in your file tree.">Meteor</a>
 						</li>
-						<li>
-							<a href="http://todomvc.derbyjs.com" data-source="http://derbyjs.com" data-content="MVC framework making it easy to write realtime, collaborative applications that run in both Node.js and browsers.">Derby</a>
-						</li>
 						<li class="routing">
 							<a href="http://todomvc-socketstream.herokuapp.com" data-source="http://www.socketstream.org" data-content="SocketStream is a fast, modular Node.js web framework dedicated to building realtime single-page apps">SocketStream</a>
 						</li>