chore(dart_frog): add example (#16)

Author: felangel

README.md

@@ -206,7 +206,7 @@ Response onRequest(RequestContext context) {
 
 ### Testing 🧪
 
-In Dart Frog, we can unit test our route handlers and middleware effectively because they are just pure functions.
+In Dart Frog, we can unit test our route handlers and middleware effectively because they are plain functions.
 
 For example, we can test our route handler above using `package:test`:
 

packages/dart_frog/example/main.dart

@@ -0,0 +1,5 @@
+import 'package:dart_frog/dart_frog.dart';
+
+Response onRequest(RequestContext context) {
+  return Response(body: 'Welcome to Dart Frog!');
+}

packages/dart_frog/pubspec.yaml

@@ -1,5 +1,5 @@
 name: dart_frog
-description: A fast, minimalistic backend framework for Dart
+description: A fast, minimalistic backend framework for Dart built by Very Good Ventures.
 version: 0.0.1-dev.2
 homepage: https://github.com/VeryGoodOpenSource/dart_frog