Nice work, but there is (IMHO) an important feature missing: hubot should appear as a member (additional user) in the direct messages list and enable talking privately to it. Something like Slack's own slackbot and/or Slack's Hubot integration. What do you think of this?
I've opened a GitHub issue on hubot-mattermost, but I have a feeling this sould be escalated to Mattermost. Should I open a new issue on Mattermost's GitHub perhaps?