New guide section on Git and GitHub

[Mojca Miklavec]

On 12 April 2018 at 04:39, Mark Anderson wrote:
> Have we thought about moving entirely to github. Using issues and projects?
> I remember there being a reason we didn't, but I don't remember what it was.

Yes, we did. Ryan even had all trac tickets imported into GitHub and
some redirection from old URLs from Trac tickets to the issue.

The reason for not proceeding were too many limitations. Like,
inability to list all tickets belonging to a particular port,
inability to show all issues assigned to you, it was impossible to
enforce consistent numbering of tickets during the initial import,
people who submitted tickets would no longer be their "authors", they
would only get an email saying "discussion continues here" for each
ticket they ever participated at.

GitHub issues could potentially work well for individual components
like macports-base, but then I'm not sure if we would be ok with
having half of issues on GitHub and the other half on Trac.

Mojca