index.erb

<form action="/charge" method="POST">
  <script
    src="https://checkout.stripe.com/checkout.js" class="stripe-button"
    data-key="pk_test_****"
    data-amount="2000"
    data-name="schaeffonline.de"
    data-description="2 widgets"
    data-image="https://cdn.shopify.com/s/files/1/0302/2969/products/great-cookie-m_and_m-cookie-03_1024x1024.jpg"
    data-locale="auto"
    data-zip-code="true"
    data-currency="eur">
  </script>
</form>