docs(tutorial/step_02): add experiment to update controller test

Add an experiment to update the controller unit test after modifying it
with the new model property.

docs/content/tutorial/step_02.ngdoc

@@ -226,6 +226,10 @@ To run the test, do the following:
 
   Refresh your browser and verify that it says "Hello, World!".
 
+* Update the unit test for the controler in ./tests/unit/controlersSpec.js to refelct the previous change. For example by adding:
+
+          expect(scope.name).toBe('World');
+
 * Create a repeater that constructs a simple table:
 
           <table>