[githubcards] request: add

[Chovin]

• Cog: githubcards
• Issue description: Feature Request
  I have my server(s) split up into projects by channel.
  I would love the ability to assign prefixes per channel or some such so that we could have a scenario like this:

#site-a
Bob: site#2
bot: *issue for site-a

#site-b
Ron: site#2
bot: *issue for site-b
John: backend#4
bot: *issue for backend repo of site-b

etc

[Kowlin]

I can understand why you want this, this is something I will look into. However I doubt I will be doing updates anymore for the current version of GHC, with the rewrite being so close to being functional.