fixed example/express3.js

examples/express3.js

@@ -4,7 +4,7 @@ const express = require('express');
 const bodyParser = require('body-parser');
 const app = express();
 
-app.use(bodyParser.json());
+app.use(bodyParser.json()); // before request handlers
 
 app.get('/api/tasks', getTasks);
 app.post('/api/tasks', saveTask);