[Docs] Add a section about joining the Core Team

Author: bbatsov

docs/modules/ROOT/pages/about/team.adoc

@@ -22,5 +22,15 @@ of the RuboCop core team, listed in the order of joining it:
 In addition, we'd like to extend a special thanks the following retired RuboCop
 core team members. Lovingly known as The Alumni:
 
-* https://github.com/yujinakayama[Yuji Nakayama]
+* https://github.com/yujinakayama[Yuji Nakayama] (also author of `guard-rubocop`)
 * https://github.com/edzhelyov[Evgeni Dzhelyov]
+
+== Joining the Core Team
+
+We're always looking for more people to join our Core Team, as there's plenty of work to go around.
+There's no formal procedure for applying to the team, but it's fairly straightforward to get an invitation
+to join it:
+
+* contribute consistently over an extended period of time (e.g. 6-12 months)
+* demonstrate a passion for what we're doing
+* eventually an invitation will be extended to you to become part of RuboCop's team