Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
The equipped monster gains 500 ATK. Monsters your opponent controls cannot change their battle positions.
--重力の斧－グラール
--Gravity Axe - Grarl
local s,id=GetID()
function s.initial_effect(c)
	aux.AddEquipProcedure(c)
	--Atk
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_EQUIP)
	e2:SetCode(EFFECT_UPDATE_ATTACK)
	e2:SetValue(500)
	c:RegisterEffect(e2)
	--pos limit
	local e4=Effect.CreateEffect(c)
	e4:SetType(EFFECT_TYPE_FIELD)
	e4:SetCode(EFFECT_CANNOT_CHANGE_POSITION)
	e4:SetProperty(EFFECT_FLAG_SET_AVAILABLE)
	e4:SetRange(LOCATION_SZONE)
	e4:SetTargetRange(0,LOCATION_MZONE)
	c:RegisterEffect(e4)
end