POST /admin/application_credits.json HTTP/1.1
Host: merchantshop.myshopify.com
Content-Type: application/json
X-Shopify-Access-Token: 35ee86casd97e9b8b10089afa4ccb654


{
  "application_credit": {
    "description": "Sorry you paid twice by mistake! Here is a $5 credit.",
    "amount": 5.0
  }
}