README: Welcome to AeroSpace Discussions!

[nikitabobko]

We’re using GitHub Discussions as a place to connect with other members of our community.

There are 6 channels:

• #all. RSS. Feed with all discussions.
• #announcements. RSS. Only maintainers can post here. Highly moderated traffic.
• #announcements-releases. RSS. Announcements about non-patch releases. Only maintainers can post here.
• #feature-ideas. RSS.
• #general. RSS.
• #questions-and-answers. RSS.

[nikitabobko]

I have updated RSS links to sort by creation date by default (otherwise some RSS readers get confused)