I do wonder if a combination of things could work:
(edit: just realized I basically said the same thing as @Wayne_Douglas above)
- move to a Slack clone like Ryver (or other) that maintains history for free; continue to have EmberJS development specific conversations on that platform
- Nudge people asking for help and support in chat to this forum (or whatever similar one is setup). I like this better than pushing people to StackOverflow (not that the forum couldn’t prompt that) because the forum should promote a better sense of community compared to SO’s drive-by mentality.
2a) Look into the styling of this forum - Is it just the default? To me, it’s hard to scan, see topics at a glance and those things don’t help make it the kind of page I want to hang around on watching for new messages, interacting with the community, etc.