This plugin already exists. It is programmed by Grooohm . I have extend the plugin minimally so all error were eliminated in my console. I hope I was able to help all the people who also had problems with this plugin.
Description: Small plugin which offers a command to teleport you to a (in the config) defined server.
License: Public Domain - unlicense.org
- /lobby - teleports you to the lobby server.
alreadyThere=You are already on the lobby server