created settings model

lib/model/settings.dart

@@ -0,0 +1,29 @@
+import '../assets/constants.dart' as constants;
+
+class Settings {
+  final String exportDirectoryPath;
+
+  Settings._({required this.exportDirectoryPath});
+
+  Map<String, dynamic> toJson() {
+    return {'exportDirectoryPath': exportDirectoryPath};
+  }
+
+  factory Settings.fromJson(Map<String, dynamic> json) {
+    return Settings._(
+      exportDirectoryPath: json['exportDirectoryPath'] as String,
+    );
+  }
+
+  factory Settings.defaults() {
+    return Settings._(
+      exportDirectoryPath: constants.defaultAndroidExportDirectory,
+    );
+  }
+
+  Settings copyWith({String? exportDirectoryPath}) {
+    return Settings._(
+      exportDirectoryPath: exportDirectoryPath ?? this.exportDirectoryPath,
+    );
+  }
+}