url-shortener/views/home.erb

<form method="POST" action="/create">
  <input type="url"
    name="url"
    pattern="https?://.+"
    placeholder="http://www.example.com/"
    style="padding: 0.5rem;"
    required />
  <input type="submit" value="Submit" style="padding: 0.5rem;" />
</form>