Onboard Julian as a member

[nebrius]

• [x] Add them to the members sections of the README and HISTORY documents.
• [x] Add them to the inclusivity@iojs.org mailing list.
• [x] Add them to the Inclusivity GitHub team.
• Slack
  • [x] Invite them to join Slack.
  • Once #111 is done, just point to the sign up page.
  • [x] Set them as an Admin.
  • [x] Invite them to the members-only channels.