Use viewport meta tag to avoid scroll on swipe

By default on the iPad when you attempt to swipe to change slide it
is also interpreted as a scroll event, causing a bouncing scroll.
Specifying the viewport means the browser does not attempt to scroll
outside the area of the slide.

views/index.erb

@@ -6,6 +6,8 @@
   <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
   <title><%= @title %></title>
 
+  <meta name="viewport" content="width=device-width"/>
+
   <link rel="stylesheet" href="<%= @asset_path %>css/reset.css" type="text/css"/>
   <link rel="stylesheet" href="<%= @asset_path %>css/showoff.css" type="text/css"/>