netpyne-149 Add validation for tutorial 3

Author: aranega

webapp/redux/reducers/data/tutorial3_steps.js

@@ -148,7 +148,8 @@ const tutorial3_steps = [
         <p>Increase the initial concentration to 0.1.</p>
       </div>
     ),
-    waitFor: 'fieldEdition'
+    waitFor: 'fieldEdition',
+    validation: '0.1'
   },
   // Update the model
   {