docs(readme): add warnings

Author: yusukebe

README.md

@@ -24,6 +24,10 @@ export default app
 
 This means you can create API routes with Hono's syntax and use a lot of Hono's built-in middleware and third-party middleware.
 
+> [!WARNING]
+>
+> `hono-remix-adapter` is currently unstable. The API may be changed without announcement in the future.
+
 ## Install
 
 ```bash

example/server/index.ts

@@ -1,21 +1,14 @@
 // server/index.ts
 import { Hono } from 'hono'
+import { poweredBy } from 'hono/powered-by'
 
-const app = new Hono<{
-  Bindings: {
-    MY_VAR: string
-  }
-}>()
+const app = new Hono()
 
-app.use(async(c, next) => {
-  await next()
-  c.header('X-Powered-By', 'Remix and Hono')
-})
+app.use(poweredBy())
 
 app.get('/api', (c) => {
   return c.json({
     message: 'Hello',
-    var: c.env.MY_VAR
   })
 })