Krampe SB3060 with trailer hitch v1.0

I've added a trailer hitch to the back of trailer so now you can pull multiple trailers behind using a dolly. It will haul everything that the in game one will haul as I left it as bulk. The capacity has been increased to 60,000L with an optional extension that will increase it to 90,000L. You can also now pick you own color too if you do not like the Krampe Red. The idea came from the one I used in FS17 that I loved so much. I have double checked on both single and MP and received no errors.