Allow hubot to mention users

[paulhammond]

Today you can do this in a script to cause a mention:

msg.send "Hey <@U02871NCZ>"

Where U02871NCZ is the internal user id of the slack user you want to mention. But... this isn't exactly intuitive, and is unlikely to be supported by most hubot scripts. We should automatically convert @paulhammond to <@U02871NCZ> in our send function.

While we're at it, we might want to do the same for @channel to <!channel> (and group, and everyone).

[evansolomon]

I feel like I've had hubot scripts use @{{username}} and I've gotten notifications for those. Am I imagining that?

[paulhammond]

Maybe... the rules around notifications on Slack are complex and you may have got some kind of notification if you have your name set up as a highlight word. But, if we want hubot-slack to consistently trigger push notifications on mobile then we'll want to send the <@U...> version.

[evansolomon]

Got it, makes sense

[kdawgwilk]

👍 for this feature

[tedsteen]

this is fixed nicely in #193