Disable Elytra Outside The End

The mod does what it says in the name

Really simple mod I made for my SMP, but maybe someone will find it useful, so I published it

No fancy features such as actionbar notification, customizing dimensions and improved logic (since it can break some mods now, probably, idk), but probably later

Mod is server-sided, but you'd better to install it on client (be ready your elytras wouldn't open even on servers without this mod, currently)