Add user list command (#427)

Co-authored-by: Matti R <matti@mdranta.net>
Co-authored-by: Norwin <noerw@noreply.gitea.io>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Norwin <git@nroo.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/427
Reviewed-by: Norwin <noerw@noreply.gitea.io>
Reviewed-by: 6543 <6543@obermui.de>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-committed-by: techknowlogick <techknowlogick@gitea.io>

main.go

@@ -54,6 +54,8 @@ func main() {
 		&cmd.CmdOpen,
 		&cmd.CmdNotifications,
 		&cmd.CmdRepoClone,
+
+		&cmd.CmdAdmin,
 	}
 	app.EnableBashCompletion = true
 	err := app.Run(os.Args)