```ruby
ActiveRecord::Rollout.configure do |config|
  # config.define_user_group do |user|
  #   user.admin?
  # end
end
```

Add group name to initializer example
user
```ruby
ActiveRecord::Rollout.configure do |config|
  # config.define_user_group :admins do |user|
  #   user.admin?
  # end
end
```
assistant