Minimal IRC server which integrates with Mattermost and Slack.

Features:

 - support direct messages / private channels / edited messages
 - auto-join/leave to same channels as on mattermost
 - reconnects with backoff on mattermost restarts
 - support multiple users
 - support channel backlog (messages when you're disconnected from
   IRC/mattermost)
 - search messages (/msg mattermost search query)
 - scrollback support (/msg mattermost scrollback #channel limit)
 - restrict to specified mattermost instances
 - set default team/server
 - WHOIS, WHO, JOIN, LEAVE, NICK, LIST, ISON, PRIVMSG, MODE, TOPIC,
   LUSERS, AWAY, KICK, INVITE support
 - support TLS (ssl)
 - support LDAP logins (mattermost enterprise) (use your ldap
   account/pass to login)
 - &users channel that contains members of all teams (if mattermost is
   so configured) for easy messaging
 - supports mattermost roles (shows admins with @ status for now)
 - gitlab auth hack by using mmtoken cookie (see
   https://github.com/42wim/matterircd/issues/29)