id: Cloaked group identifier.
root: Group creation message.
authors: Authors in group.
key: Group key. Add this when we have "better GraphQL security".
exact names TBD, but something like:
Create new group.
Return array of groups that you are a member of.
Return group identified by
Add array of members to group.
Note that SSB-Tribes only allows 15 members to be added per message.