fix SESSION at login, add navbar at logout

public/index.php

@@ -55,8 +55,10 @@ $app->get('/blog/{slug}', function (Request $request, Response $response, array
 });
 
 $app->get('/logout', function(Request $request, Response $response, array $args) {
-
     unset($_SESSION['username']);
+    addNavbar($response);
+    $response->getBody()->write('logged out');
+    addFooter($response);
     return $response;
 });
 
@@ -73,8 +75,11 @@ $app->map(['GET', 'POST'],'/login', function (Request $request, Response $respon
     } else {
         $postdata = $request->getParsedBody();
         if ($postdata['username'] == 'gebruiker' && $postdata['password'] == 'abcd') {
-            $response->getBody()->write('logged in');
             $_SESSION['username'] = $postdata['username'];
+            addNavbar($response);
+            $response->getBody()->write('logged in');
+            addFooter($response);
+            
         } else {
             $response->getBody()->write('username and/or password incorrect');
         }