use lnurlpay.currency when creating invoices.

Author: fiatjaf

src/lnurl.js

@@ -104,6 +104,7 @@ module.exports = (app, payListen, model, auth, ln) => async {
     , metadata: invoiceMetadata
     , webhook: endpoint.webhook
     , lnurlpay_endpoint: endpoint.id
+    , currency: endpoint.currency
     })
 
     let successAction