Users groups

[rafalp]

User should have one primary group.

User can have zero or more secondary group memberships.

Registered users are set as members of "default" group.

Users get permissions from user groups.

Full draft

TODO

• [x] Group model
• [x] Default groups
• [x] Assign default group to user
• [x] Assign secondary groups to user
• [x] Update user's ACL key when their group memberships change

GraphQL

• [x] Select
• [ ] Get members count
• [ ] Create
• [ ] Update
• [ ] Delete
• [ ] Reorder