Add directive for smooth scrolling to anchor

app/assets/javascripts/darkswarm/directives/smooth_scroll_to.js.coffee

@@ -0,0 +1,15 @@
+Darkswarm.directive "ofnSmoothScrollTo", ($location, $document)->
+  # Onclick sets $location.hash to attrs.ofnScrollTo
+  # Then triggers $document.scrollTo
+  restrict: 'A'
+  link: (scope, element, attrs)->
+    element.bind 'click', (ev)->
+      ev.stopPropagation()
+      $location.hash attrs.ofnScrollTo
+      target = $("a[name='#{attrs.ofnSmoothScrollTo}']")
+      # Scrolling is confused by our position:fixed top bar and page alert bar
+      # - add an offset to scroll to the correct location, plus 5px buffer
+      offset  = $("nav.top-bar").height()
+      offset += $(".page-alert.move-down").height()
+      offset += 5
+      $document.scrollTo target, offset, 1000