fixed up Ring shape init method because the drawFunc API slightly changed

src/shapes/Ring.js

@@ -32,8 +32,9 @@
             // call super constructor
             Kinetic.Shape.call(this, config);
             this.className = 'Ring';
+            this.setDrawFunc(this._drawFunc);
         },
-        drawFunc: function(context) {
+        _drawFunc: function(context) {
             context.beginPath();
             context.arc(0, 0, this.getInnerRadius(), 0, PIx2, false);
             context.moveTo(this.getOuterRadius(), 0);

test/unit/shapes/Ring-test.js

@@ -11,7 +11,8 @@ suite('Ring', function() {
           outerRadius: 90,
           fill: 'green',
           stroke: 'black',
-          strokeWidth: 4
+          strokeWidth: 4,
+          draggable: true
       });
       layer.add(ring);
       stage.add(layer);