Freeze angle to entity

whenever I use this code to spawn my entity it will move with the player and the angle of it will change depending on where the player looks



	concommand.Add("createtub", function(ply)
bt1 = ents.Create( "prop_outline" )
bt1:SetParent( ply, 1 )
bt1:SetLocalPos( Vector(0,0,10) )
bt1:SetModelScale( bt1:GetModelScale() * .5, 0 )
bt1:SetCollisionGroup(COLLISION_GROUP_IN_VEHICLE)
bt1:SetAngles( Angle(0,0,0) )
bt1:Spawn()


concommand.Add("removetub",function()
bt1:Remove()
end)

end)

How would I make it so the entity still moves with the player but the angle never changes?