Add companies list

Closes #90

Author: nhooyr

README.md

@@ -165,3 +165,9 @@ about performant WebSocket servers.
 If you want a library that gives you absolute control over everything, this is the library,
 but for most users, the API provided by nhooyr/websocket will fit better as it is nearly just
 as performant but much easier to use correctly and idiomatic.
+
+## Users
+
+- [coder.com](https://coder.com)
+
+If your company is using this library, please feel free to open a PR.