some more js love - update the docs with tabs/pills plugin

docs/assets/js/application-scrollspy.js

@@ -0,0 +1,39 @@
+// scroll spy logic
+// ================
+$(function () {
+
+  var activeTarget,
+     position = {},
+     $window = $(window),
+     nav = $('body > .topbar li a'),
+     targets = nav.map(function () {
+       return $(this).attr('href');
+     }),
+     offsets = $.map(targets, function (id) {
+       return $(id).offset().top;
+     });
+
+  function setButton(id) {
+   nav.parent("li").removeClass('active');
+   $(nav[$.inArray(id, targets)]).parent("li").addClass('active');
+  }
+
+  function processScroll(e) {
+   var scrollTop = $window.scrollTop() + 10, i;
+   for (i = offsets.length; i--;) {
+     if (activeTarget != targets[i] && scrollTop >= offsets[i] && (!offsets[i + 1] || scrollTop <= offsets[i + 1])) {
+       activeTarget = targets[i];
+       setButton(activeTarget);
+     }
+   }
+  }
+
+  nav.click(function () {
+   processScroll();
+  });
+
+  processScroll();
+
+  $window.scroll(processScroll);
+
+})