Fix Docker environment configuration

[sjednac]

I've tested the whole process, including the guided GitHub app setup, on my personal account. There were two minor issues, that I needed to fix for the Docker environment to work:

• The process needs to bind to 0.0.0.0 when run inside Docker. Otherwise, port forwarding won't work.
• The argument of the Docker command should take credentials location as an absolute path inside
  Docker, as the CWD is set to /data.

Now it works like a charm! 🎉 I will test it on an actual org account in the following week.

[Copilot]

Pull Request Overview

This PR fixes Docker environment configuration issues for the GitHub backup app by addressing network binding and path resolution problems.

• Adds a configurable host binding option to support Docker port forwarding
• Updates Docker command documentation to use absolute paths for credential files

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
github_backup/create_github_app.py	Adds --host parameter and updates server binding to use configurable host
README.md	Updates Docker command examples to bind to 0.0.0.0 and use absolute credential paths

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}