How can I put my new code into the omnibus docker image?

I have got gitlab-ce 10.6.4 omnibus docker image, and creat a container with it. It works good.
Now I make some new features for 10.6.4, and I want to put my new code into the omnibus docker image.
I have tried the omnibus-gitlab project to make a deb packege. But I faild because the GFW block many sites.
So can I directly put my new code in the container and commit a new docker image?
Thanks!