Try not to worry about it. It is not torturing to her. It is much better to keep her as an inside kitty. It will take time and patience on your part to train her to stay inside. She will adjust in time.
When she starts to scratch at the door, get her attention by playing with her. If she continues, you firmly tell her no and try to distract her with something else. If it gets to be too much, use a squirt bottle on her. I had to do these things myself when I took in a stray cat who I named Toby and he did just fine. It could take a couple of days, it could take a couple of weeks, depends on how consistant you are with this and depends on the cat. Once you are satisfied that you have suceeded in keeping her in, then, if you want, you can start to train her on a leash to take her outside.
Good luck and keep us posted.
By the way, congratulations on your new kitty Maddie and i'm so glad that you got her from a shelter.