GoUsers: add Reface to Ukraine section

This Ukrainian startup has a lot of backend services written in Go.

Change-Id: I190a784cae80e3b94742cceb3086396e66db156e
Reviewed-on: https://go-review.googlesource.com/c/wiki/+/644595
Auto-Submit: Ian Lance Taylor <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Commit-Queue: Ian Lance Taylor <[email protected]>

Author: alexandear

GoUsers.md

@@ -1354,6 +1354,7 @@ Certificate Expiry Monitor Controller monitors the expiration of TLS certificate
   * [Diligences](https://diligences.com/)
   * [ElementalsWeb](https://www.elementalsweb.com/)
   * [monobank](https://monobank.ua/)
+  * [Reface](https://reface.ai/)
   * [ROZETKA](https://rozetka.com.ua/)
   * [VP Software](https://vp.software/) - [tech blog](https://vp.software/insights) - software development company
 ### United Arab Emirates