app/controllers/groups_controller.rb

@@ -0,0 +1,5 @@
+class GroupsController < ApplicationController
+  def index
+    render jsonapi: Group.where(parent_id: nil), include: [children: [children: [:children]]]
+  end
+end

app/helpers/groups_helper.rb

@@ -0,0 +1,2 @@
+module GroupsHelper
+end

app/models/group.rb

@@ -0,0 +1,7 @@
+class Group < ApplicationRecord
+    validates :name, uniqueness: true
+    validates :name, :order, presence: true
+
+    has_many :children, class_name: 'Group', foreign_key: 'parent_id'
+    belongs_to :parent, class_name: 'Group', optional: true
+end

app/serializers/serializable_group.rb

@@ -0,0 +1,7 @@
+class SerializableGroup < JSONAPI::Serializable::Resource
+  type 'group'
+
+  attributes :name, :icon
+
+  has_many :children
+end

config/routes.rb

@@ -1,4 +1,5 @@
 Rails.application.routes.draw do
+  resources :groups, only: :index
   resources :guests do
     post :import, on: :collection
   end

db/migrate/20240811142121_create_groups.rb

@@ -0,0 +1,13 @@
+class CreateGroups < ActiveRecord::Migration[7.1]
+  def change
+    create_table :groups, id: :uuid do |t|
+      t.string :name, null: false
+      t.string :icon
+      t.integer :order, null: false, default: 1
+
+      t.timestamps
+    end
+
+    add_index :groups, :name, unique: true
+  end
+end

db/migrate/20240811143801_add_parent_to_group.rb

@@ -0,0 +1,5 @@
+class AddParentToGroup < ActiveRecord::Migration[7.1]
+  def change
+    add_reference :groups, :parent, type: :uuid, index: true, foreign_key: { to_table: :groups }
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.1].define(version: 2024_07_24_181853) do
+ActiveRecord::Schema[7.1].define(version: 2024_08_11_143801) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -26,6 +26,17 @@ ActiveRecord::Schema[7.1].define(version: 2024_07_24_181853) do
     t.datetime "updated_at", null: false
   end
 
+  create_table "groups", id: :uuid, default: -> { "gen_random_uuid()" }, force: :cascade do |t|
+    t.string "name", null: false
+    t.string "icon"
+    t.integer "order", default: 1, null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.uuid "parent_id"
+    t.index ["name"], name: "index_groups_on_name", unique: true
+    t.index ["parent_id"], name: "index_groups_on_parent_id"
+  end
+
   create_table "guests", id: :uuid, default: -> { "gen_random_uuid()" }, force: :cascade do |t|
     t.string "first_name"
     t.string "last_name"
@@ -82,6 +93,7 @@ ActiveRecord::Schema[7.1].define(version: 2024_07_24_181853) do
     t.index ["name"], name: "index_tags_on_name", unique: true
   end
 
+  add_foreign_key "groups", "groups", column: "parent_id"
   add_foreign_key "seats", "guests"
   add_foreign_key "seats", "tables_arrangements", on_delete: :cascade
   add_foreign_key "taggings", "tags"

db/seeds.rb

@@ -5,6 +5,7 @@ Expense.delete_all
 Guest.delete_all
 ActsAsTaggableOn::Tagging.delete_all
 ActsAsTaggableOn::Tag.delete_all
+Group.delete_all
 
 Expense.create!(name: 'Photographer', amount: 3000, pricing_type: 'fixed')
 Expense.create!(name: 'Country house', amount: 6000, pricing_type: 'fixed')
@@ -21,6 +22,35 @@ Expense.create!(name: 'Transportation', amount: 3000, pricing_type: 'fixed')
 Expense.create!(name: 'Invitations', amount: 200, pricing_type: 'fixed')
 Expense.create!(name: 'Cake', amount: 500, pricing_type: 'fixed')
 
+Group.create!(name: "Jim's guests", icon: "pi pi-heart").tap do |parent|
+  parent.children.create!(name: "Jim's family", icon: "pi pi-users").tap do |family|
+    family.children.create!(name: "Jim's close family", icon: "pi pi-home")
+    family.children.create!(name: "Jim's cousins", icon: "pi pi-home")
+    family.children.create!(name: "Jim's relatives", icon: "pi pi-home")
+  end
+  parent.children.create!(name: "Jim's friends", icon: "pi pi-bullseye")
+  parent.children.create!(name: "Jim's work", icon: "pi pi-desktop").tap do |work|
+    work.children.create!(name: "Jim's besties at work", icon: "pi pi-briefcase")
+  end  
+end
+
+Group.create!(name: "Pam's guests", icon: "pi pi-heart-fill").tap do |parent|
+  parent.children.create!(name: "Pam's family", icon: "pi pi-users").tap do |family|
+    family.children.create!(name: "Pam's close family", icon: "pi pi-home")
+    family.children.create!(name: "Pam's cousins", icon: "pi pi-home")
+    family.children.create!(name: "Pam's relatives", icon: "pi pi-home")
+  end
+  parent.children.create!(name: "Pam's friends", icon: "pi pi-bullseye")
+  parent.children.create!(name: "Pam's work", icon: "pi pi-desktop").tap do |work|
+    work.children.create!(name: "Pam's besties at work", icon: "pi pi-briefcase")
+  end  
+end
+
+Group.create!(name: "Common guests", icon: "pi pi-users").tap do |parent|
+  parent.children.create!(name: "College friends", icon: "pi pi-calculator")
+  parent.children.create!(name: "High school friends", icon: "pi pi-crown")
+  parent.children.create!(name: "Childhood friends", icon: "pi pi-envelope")
+end
 
 samples = {
   close_family_a: 10,

spec/factories/groups.rb

@@ -0,0 +1,7 @@
+FactoryBot.define do
+  factory :group do
+    name { "MyString" }
+    icon { "MyString" }
+    order { 1 }
+  end
+end

spec/models/group_spec.rb

@@ -0,0 +1,5 @@
+require 'rails_helper'
+
+RSpec.describe Group, type: :model do
+  pending "add some examples to (or delete) #{__FILE__}"
+end