content: import React from 'react'
  
  import { Link } from 'react-router-dom'
  
  export const Header = () => (
    <header>
      <nav>
        <ul>
          <li><Link to='/'>Home</Link></li>
          <li><Link to='/user-profile'>Roster</Link></li>
          <li><Link to='/not-found'>404</Link></li>
        </ul>
      </nav>
    </header>
  )