Support for multiple Discord channels

[LukeMoll]

It'd be nice to have multiple channel-to-channel mappings from Discord to Slack, perhaps with a separate config file where Slack and Discord channels could be listed.

[ffvdgames]

I've achieved this by cloning the bridge folder, renaming the bot and key files so they're unique from the others, updating the webhook and channel name in the key files, and changing the code in the bot script slightly so it redirects to the newly named key files. Super duper easy to do. No hiccups so far running three of them on my Pi.

It's an ugly little hack, but I think that's the closest we're gonna get for now.

[fortepc]

I think the Miscord's way of doing multiple channel mappings would be a great thing to adopt. I plan on running a slack bridge at the same time as miscord's messenger bridge to have our chat group on 3 separate apps.