Fix broken sample code

README.md

@@ -37,16 +37,16 @@ class MongoDbPool extends ConnectionPool<Db> {
 /**
  * Retrieve and release a connection from the pool.
  */
-app.Interceptor(r'/.*')
-dbInterceptor(MongoDbPool pool) {
+@app.Interceptor(r'/.*')
+dbInterceptor(@app.Inject() MongoDbPool pool) {
 
   //get a connection
-  pool.getConnection().then((managedConnection) {
+  return pool.getConnection().then((managedConnection) {
 
     //save the connection in the attributes map
     app.request.attributes["conn"] = managedConnection.conn;
 
-    app.chain.next(() {
+    return app.chain.next(() {
       if (app.chain.error is ConnectionException) {
         //if a connection is lost, mark it as invalid, so the pool can reopen it
         //in the next request