update production host

Omniauth_API_Document.md

@@ -2,7 +2,7 @@
 ## Hosts
  - preparing: https://preparing.kdanmobile.com:3002/
  - staging: https://staging.kdanmobile.com:3002/
- - production: https://cloud.kdanmobile.com/
+ - production: https://auth.kdanmobile.com/
 
 ## APIs
 ### **POST** api/v3/verification/through\_omniauth