How to save MBilliards to map

Been trying for an hour to figure this out but no luck yet.
https://www.facepunch.com/threads/1054212-MBilliards

On Elevator Source there are 2 pool tables that get spawned, if some one could direct me to how that is done that would be great!
Iv tried permaprops, M.D.E, persistent nothing seems to work.

Use

hook.Add to create a hook for

GM:InitPostEntity and

GM:PostCleanupMap, and in the hook use

ents.Create to spawn the billiards.

Do it in a serverside autorun file.

Ok thanks!