Implement bitcoin donations via BTCPay

app/services/btcpay_manager/fetch_invoice.rb

@@ -0,0 +1,14 @@
+module BtcpayManager
+  class FetchInvoice < BtcpayManagerService
+    def initialize(invoice_id:)
+      @invoice_id = invoice_id
+    end
+
+    def call
+      invoice = get "/invoices/#{@invoice_id}"
+      payment_methods = get "/invoices/#{@invoice_id}/payment-methods"
+      invoice["paymentMethods"] = payment_methods
+      invoice
+    end
+  end
+end