[New Feature] create a new GitHub App for the app generator

[Paul Williams]

Is your feature request related to a problem? Please describe.
Once the feature request #12 is incorporated user would have to pass GitHub token every time.

Describe the solution you'd like
This can be avoided by making this as an GitHub App to gain access in order to create repository, commit and push the files

Additional context
https://developer.github.com/apps/building-github-apps/