Trying to teach: Shut the door

Everyday, Kai lets herself in the backdoor but has not figured out how to shut the back door. So today I have started the process, and I hope it works but she is a little noise shy when she actually shuts the door. I hold a piece of treat up at the door and she has to jump on the door and have it close to get the treat. It is going to be a long process. But she did do it several times, I am not sure she would do it without the treat. I say "Shut the door" and waggle the treat anyone know a way to narrow that down so she does not have to listen to a whole sentence. If I just say shut, she sits. I just got back from Atlanta where it was around 60 to 70 degrees and now it is about 30 to 40 degrees and I think the door shutting trick is a must. She only comes in because it is cold or when she wants me to play with her. She is such a sweet dog and I just found out she got to play with one of my best friends dogs while I was away and she was boarding, what fun. I am so happy that we rescued her and the neighbor kids love her. I usually have 10 kids hanging out by the fence after school so they can say hello. The only time it becomes a problem is when a dog comes by, she would rather bark at the dog then play with the kids and the kids get very disappointed. Now with us pretty much staying at home, I think that she will get back into her training and remembering how to walk the streets and maybe, just maybe, shutting the door on command.