update: add username search tool

README.md

@@ -1766,6 +1766,7 @@ Hello! On my Twitter account [@cyb_detective](https://linktr.ee/cyb_detective) I
 | [Nameberry](https://nameberry.com/search?q=john) | When you are looking for mentions of a person on social media, remember that one name can have dozens of different spelling variations. Ideally, you should check them all, or at least the most popular ones. |
 | [WhatsMyName](https://whatsmyname.app) | With Holehe and Maigret, WhatsMyName is one of the most powerful Username enumeration tools. |
 | [Go Sherlock](https://github.com/Longwater1234/go-sherlock) | #GO version of Project Sherlock (https://github.com/sherlock-project/sherlock…). It's quite fast. Checks if a user with a certain nickname exists on a thousand sites in a few tens of seconds. |
+| [User Searcher](https://www.user-searcher.com) | User-Searcher is a powerful and free tool to help you search username in 2000+ websites. |
 
 
 [](#phone-numbers)Phone numbers