agrega relacion de delegate para searchbar en view controller

ContactsApp/Base.lproj/Main.storyboard

@@ -56,6 +56,7 @@
                     <navigationItem key="navigationItem" id="U0h-dc-vbE"/>
                     <connections>
                         <outlet property="contactsTable" destination="dBj-cU-Ugw" id="8YS-LO-fy0"/>
+                        <outlet property="searchBar" destination="2yO-jM-dTD" id="4EW-JC-tfj"/>
                         <segue destination="i2T-MY-6qf" kind="show" identifier="gotocontact" id="1Ts-QM-UT7"/>
                     </connections>
                 </viewController>

ContactsApp/ContactsViewController.swift

@@ -11,6 +11,7 @@ import ContactsUI
 
 class ContactsViewController: UIViewController {
     
+    @IBOutlet weak var searchBar: UISearchBar!
     @IBOutlet weak var contactsTable: UITableView!
     var contactStructArray = [ContactStruct]()
     var contactStruct : ContactStruct?