Slack bot should join a channel when we provision it.

[Half-Shot]

I spent a hour wondering why slack wasn't sending events to me, before realising it wasn't in the channel. We should probably invite the bot to the channel.

[ashwinvis]

I second this. If not automated, it would be useful to tell the user to run

/invite @riot_bridge

inside the Slack channel, while setting up the integration.

[ashwinvis]

Probably related https://github.com/vector-im/riot-web/issues/7978

[auscompgeek]

The *.invite methods require the OAuth user channels:write scope, which by the look of things the Slack app currently doesn't request.

[BillyZeGame]

I'm stuck. By bot is invited, and still nothing moves to riot aka element. Anyone able to kindly assist me? In Slack: OK In Element: KO