Add fullstack example

examples/fullstack/backend/config/cors.ts

@@ -0,0 +1,19 @@
+import { defineConfig } from '@adonisjs/cors'
+
+/**
+ * Configuration options to tweak the CORS policy. The following
+ * options are documented on the official documentation website.
+ *
+ * https://docs.adonisjs.com/guides/security/cors
+ */
+const corsConfig = defineConfig({
+  enabled: true,
+  origin: true,
+  methods: ['GET', 'HEAD', 'POST', 'PUT', 'DELETE'],
+  headers: true,
+  exposeHeaders: [],
+  credentials: true,
+  maxAge: 90,
+})
+
+export default corsConfig