Add a has_many through association to the dummy app

test/dummy/app/models/membership.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Membership < ApplicationRecord
+  belongs_to :user
+  belongs_to :organization
+end

test/dummy/app/models/organization.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Organization < ApplicationRecord
+  has_many :memberships
+  has_many :users, through: :memberships
+end

test/dummy/app/models/user.rb

@@ -2,7 +2,7 @@
 
 class User < ApplicationRecord
   before_create :foo, -> () {}
-  validates :name, presence: true
+  validates :first_name, presence: true
   has_one :profile
   scope :adult, -> { where(age: 18..) }
 

test/dummy/db/migrate/20240503152928_create_organizations.rb

@@ -0,0 +1,9 @@
+class CreateOrganizations < ActiveRecord::Migration[7.1]
+  def change
+    create_table :organizations do |t|
+      t.string :name
+
+      t.timestamps
+    end
+  end
+end

test/dummy/db/migrate/20240503153021_create_memberships.rb

@@ -0,0 +1,10 @@
+class CreateMemberships < ActiveRecord::Migration[7.1]
+  def change
+    create_table :memberships do |t|
+      t.references :user, null: false, foreign_key: true
+      t.references :organization, null: false, foreign_key: true
+
+      t.timestamps
+    end
+  end
+end

test/dummy/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_04_03_145625) do
+ActiveRecord::Schema[7.1].define(version: 2024_05_03_153021) do
   create_table "composite_primary_keys", primary_key: ["order_id", "product_id"], force: :cascade do |t|
     t.integer "order_id"
     t.integer "product_id"
@@ -19,6 +19,21 @@
     t.datetime "updated_at", null: false
   end
 
+  create_table "memberships", force: :cascade do |t|
+    t.integer "user_id", null: false
+    t.integer "organization_id", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["organization_id"], name: "index_memberships_on_organization_id"
+    t.index ["user_id"], name: "index_memberships_on_user_id"
+  end
+
+  create_table "organizations", force: :cascade do |t|
+    t.string "name"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+  end
+
   create_table "posts", force: :cascade do |t|
     t.string "title"
     t.text "body"
@@ -34,4 +49,6 @@
     t.datetime "updated_at", null: false
   end
 
+  add_foreign_key "memberships", "organizations"
+  add_foreign_key "memberships", "users"
 end