Create management portal in Flutter #39

web/repertory/lib/screens/add_mount_screen.dart

@@ -129,7 +129,12 @@ class _AddMountScreenState extends State<AddMountScreen> {
                   if (!validateSettings(_settings[_mountType]!, failed)) {
                     for (var key in failed) {
                       ScaffoldMessenger.of(context).showSnackBar(
-                        SnackBar(content: Text("'$key' is not valid")),
+                        SnackBar(
+                          content: Text(
+                            "'$key' is not valid",
+                            textAlign: TextAlign.center,
+                          ),
+                        ),
                       );
                     }
                     return;