Use minetest.raillike_group, do not connect rails with other raillike

functions.lua

@@ -217,7 +217,15 @@ end
 
 function boost_cart:get_rail_groups(additional_groups)
 	-- Get the default rail groups and add more when a table is given
-	local groups = {dig_immediate = 2, attached_node = 1, rail = 1, connect_to_raillike = 1}
+	local groups = {
+		dig_immediate = 2,
+		attached_node = 1,
+		rail = 1,
+		connect_to_raillike = 1
+	}
+	if minetest.raillike_group then
+		groups.connect_to_raillike = minetest.raillike_group("rail")
+	end
 	if type(additional_groups) == "table" then
 		for k, v in pairs(additional_groups) do
 			groups[k] = v