Add DaangnPay to ADOPTERS.md (#1668)

Signed-off-by: Byungjin Park (Claud) <posquit0.bj@gmail.com>

Signed-off-by: Byungjin Park (Claud) <posquit0.bj@gmail.com>

ADOPTERS.md

@@ -4,6 +4,7 @@
 
 - [Amadeus](https://amadeus.com/)
 - [Container Solutions](http://container-solutions.com/)
+- [DaangnPay](https://www.daangnpay.com/)
 - [Epidemic Sound](https://www.epidemicsound.com/)
 - [Form3](https://www.form3.tech/)
 - [Heureka Group](https://heureka.group)