Link to rubytalk.org as archive for Ruby-Talk mailing list

[gschlager]

I already mentioned this on the Ruby-Talk mailing list:

The mailman page is still pointing to the outdated Ruby-Forum. I wonder if it would make sense to link to the up-to-date Discourse mirror instead? And maybe even add it as an additional archive on the Ruby mailing list overview page?

[Quintus]

Mh, opinions? @hsbt @stomar ?

[hsbt]

I confirmed ruby-talk is a dead link on the mailman dashboard. I have plan for server maintenance of lists.ruby-lang.org in this spring. I replace it with its time.