So as requested 1.1.0 has some new features

• The ability to either whitelist specific players (like before) or blacklist instead. Useful for extra hardcore servers where you want all players to have this effect but not admins
• The ability to limit the plugin to a single world. useful if you use Multiverse

If you had 1.0.0 installed you should delete your config.yml and let it regenerate (or copy the example from the Spigot page)