Need help with spacebuild!!!

I have recently decided that i would like to host a SpaceBuild Server on garrysmod, but my problem is I dont know how to change the gravity. I know how to do the “rcon sv_gravity XXXX” command but thats not what i want. I do believe that I have to change a command line in one of the gamemode files such as init.lua or something. Any suggestions? I will post what i think may need to be changed but im not 100% sure. (P.S this is Spacebuild 3)

---------			Std. Env Stuff				---------

if k == "BrushEnvID" then
	self.ID = v
	if SB_Environments_Brush_List[self.ID] then ErrorNoHalt("NON FATALE ERROR: THERE ARE MULTIPLE USES OF " .. self.ID .. " AS A ENVIRONMENT BRUSH! OVERRIDING!

") end

	SB_Environments_Brush_List[self.ID] = self
elseif k == "ParentBrushEnvID" then
	self.ParentID = v
elseif k == "Gravity" then
	self.sbenvironment.gravity = v
elseif k == "Atmosphere" then
	self.sbenvironment.atmosphere = v
elseif k == "Pressure" then
	self.sbenvironment.pressure = v
elseif k == "Temp" then
	self.sbenvironment.temperature = v
elseif k == "Oxygen" then
	self.sbenvironment.air.o2 = v
elseif k == "Carbon_Dioxide" then
	self.sbenvironment.air.co2 = v
elseif k == "Nitrogen" then
	self.sbenvironment.air.n = v
elseif k == "Hydrogen" then
	self.sbenvironment.air.h = v
elseif k == "AirThickness" then
	self.sbenvironment.air.AirThickness = v
elseif k == "Habitable" then
	self.sbenvironment.habitable = v
elseif k == "Stable" then
	self.sbenvironment.unstable = (v ~= 1)