Fall Damage Help

I recently started coding my own gamemode and all things I have tried on the internet for my fall damage to always be 0 did not work.
I have derived my gamemode from base, I don’t know if thats why it is doing this but I really need someone to help with this.

I tried this and variations of it!

function GM:GetFallDamage( ply, speed )
         return 0


hook.Add("GetFallDamage", "NoFallDamage", function(ply, speed)
   return 0

I put this in init.lua, correct?

[editline]16th June 2014[/editline]