Fix setUsername request parameter

API-Docs.md

@@ -181,7 +181,7 @@ __________________________________________________________________
 ```
 {
   userID: string, //local user id normally, public user id if adminUserID is specified
-  userName: string,
+  username: string,
   //optional
   adminUserID: string //This is if you want to change someone elses username from the admin account
 }