Add direct link to this build on TeamCity in Slack message

[bytenik]

No description provided.

[tomfulton]

👍

[marcellscarlett]

👍

[johncrim]

Couldn't agree more, this would be an extremely valuable improvement - while you're changing the message, it would be great to add the build number, too.

[stuartsoft]

This is now partially available in my pull request #25, which among other things, includes the ability to send a TC permalink with the slack message when a build fails.