Allow set customer Id on button parameter

[oismaelash]

<button 
          className="css style SS_ProductCheckout" 
          type="button"
          data-id="2" 
          data-email="x@x.com"

data-customerId="cus_abc"

          data-url="http://localhost:1337"> Subscribe - Pro - Mensal </button>

[nishekh-e-r]

@oismaelash We will add this feature in the coming version. Thanks for pointing out.