Support option for to set user name and email globally

[cboettig]

Is your feature request related to a problem? Please describe.

I use this integration in large courses teaching git from university-managed Jupyterhubs. Overall the experience is excellent but a few things always frustrate students that I think could be addressed.

When a student first uses the tool they need to set their committer name and email. Sometimes the system pops open a helpful dialogue box for this. This is great as it does not assume the student is already an expert in bash. However, this dialogue has no mechanism to indicate a --global config, and only offers a repo-level configuration.

Other students see an error message instead of the dialogue box, like this:

Author identity unknown *** Please tell me who you are. Run git config --global user.email "you@example.com" git config --global user.name "Your Name" to set your account's default identity. Omit --global to set the identity only in this repository

While I appreciate the helpful error message (especially this time including the suggestion to use --global by default!), students have no idea where or how to run this. Also I'm not sure why this error is displayed instead of the dialogue box (that seems like a bug to me).

Describe the solution you'd like

Whenever a user name /email is not set, thus preventing a commit, I would like the application to present the dialog box. I would also suggest providing a 'check box' (similar to what we get on the clone dialog) allowing users to make this setting global.

[cboettig]

I think all we need is a checkbox to set this globally on

jupyterlab-git/src/widgets/AuthorBox.ts

Line 9 in bb5ced6

export class GitAuthorForm

, but I don't know any typescript...