added documentation for umbStickyBar

src/Umbraco.Web.UI.Client/src/common/directives/components/umbstickybar.directive.js

@@ -1,3 +1,27 @@
+/**
+@ngdoc directive
+@name umbraco.directives.directive:umbStickyBar
+@restrict A
+
+@description
+Use this directive make an element sticky and follow the page when scrolling.
+
+<h3>Markup example</h3>
+<pre>
+    <div ng-controller="Umbraco.Controller as vm">
+
+        <div
+           class="my-sticky-bar"
+           umb-sticky-bar
+           scrollable-container=".container">
+        </div>
+
+    </div>
+</pre>
+
+@param {string} scrollableContainer Set the class (".element") or the id ("#element") of the scrollable container element.
+**/
+
 (function() {
    'use strict';