Incorrect Tailwind config

I won't fork for such a small change. 

Your `tailwind.config.js` is pointing to the `pages` folder, but you are implementing next's experimental `app` folder so no tailwind styling is being generated.
```js
(...)
content: [
    "./pages/**/*.{js,ts,jsx,tsx}",
    (...)
```

Should be
```js
(...)
content: [
    "./app/**/*.{js,ts,jsx,tsx}",
    (...)
```