Adds attack/release example in site's sidebar

Author: alemangui

site/index.html

@@ -30,6 +30,7 @@
             <a href="#sound-from-input" class="menu-item">From your microphone</a>
             <a href="#sound-from-function" class="menu-item">From a function</a>
             <div class="menu-subtitle">Add effects</div>
+            <a href="#attack-release" class="menu-item">Attack-release</a>
             <a href="#delay" class="menu-item">Delay</a>
             <a href="#ping-pong-delay" class="menu-item">Ping-pong delay</a>
             <a href="#dub-delay" class="menu-item">Dub delay</a>