Update README with example

README.md

@@ -7,3 +7,58 @@ INI parser for HyperTuner written in Dart.
 ## Roadmap
 
 Checkout Roadmap issue: <https://github.com/hyper-tuner/ini_parser/issues/2>
+
+## Example usage
+
+from `example/save_as_json.dart`:
+
+```dart
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:ini_parser/ini_parser.dart';
+import 'package:path/path.dart' as p;
+
+void main() async {
+  final timer = Stopwatch()..start();
+  const fileNames = [
+    {
+      'ecosystem': 'speeduino',
+      'name': '202207',
+    },
+    {
+      'ecosystem': 'fome',
+      'name': 'fome_proteus_f4',
+    },
+  ];
+
+  for (final fileName in fileNames) {
+    final raw = File(
+      p.join(
+        Directory.current.path,
+        'test/data/${fileName['ecosystem']}/ini/${fileName['name']}.ini',
+      ),
+    ).readAsStringSync();
+    final config = await INIParser(raw).parse();
+    final json = const JsonEncoder.withIndent('  ').convert(config);
+
+    File(
+      p.join(
+        Directory.current.path,
+        'test/data/${fileName['ecosystem']}/json/${fileName['name']}.json',
+      ),
+    ).writeAsStringSync(json);
+  }
+
+  // ignore: avoid_print
+  print('Done in ${timer.elapsedMilliseconds}ms');
+}
+```
+
+Compile and run:
+
+```bash
+dart compile exe example/save_as_json.dart
+
+./example/save_as_json
+```

example/save_as_json.dart

@@ -24,12 +24,8 @@ void main() async {
         'test/data/${fileName['ecosystem']}/ini/${fileName['name']}.ini',
       ),
     ).readAsStringSync();
-    final parser = INIParser(raw);
-
-    final config = await parser.parse();
-
-    const encoder = JsonEncoder.withIndent('  ');
-    final json = encoder.convert(config);
+    final config = await INIParser(raw).parse();
+    final json = const JsonEncoder.withIndent('  ').convert(config);
 
     File(
       p.join(