add models

app/models/item.rb

@@ -0,0 +1,7 @@
+class Item < ApplicationRecord
+  # model association
+  belongs_to :todo
+
+  # validation
+  validates_presence_of :name
+end

app/models/todo.rb

@@ -0,0 +1,7 @@
+class Todo < ApplicationRecord
+    # model association
+    has_many :items, dependent: :destroy
+
+    # validations
+    validates_presence_of :title, :created_by
+end

db/migrate/20211110194428_create_todos.rb

@@ -0,0 +1,10 @@
+class CreateTodos < ActiveRecord::Migration[6.1]
+  def change
+    create_table :todos do |t|
+      t.string :title
+      t.string :created_by
+
+      t.timestamps
+    end
+  end
+end

db/migrate/20211110194855_create_items.rb

@@ -0,0 +1,11 @@
+class CreateItems < ActiveRecord::Migration[6.1]
+  def change
+    create_table :items do |t|
+      t.string :name
+      t.boolean :done
+      t.references :todo, null: false, foreign_key: true
+
+      t.timestamps
+    end
+  end
+end

spec/models/item_spec.rb

@@ -0,0 +1,10 @@
+require 'rails_helper'
+
+RSpec.describe Item, type: :model do
+  # Association test
+  # ensure an item record belongs to a single todo record
+  it { should belong_to(:todo) }
+  # Validation test
+  # ensure column name is present before saving
+  it { should validate_presence_of(:name) }
+end

spec/models/todo_spec.rb

@@ -0,0 +1,11 @@
+require 'rails_helper'
+
+RSpec.describe Todo, type: :model do
+  # Association test
+  # ensure Todo model has a 1:m relationship with the Item model
+  it { should have_many(:items).dependent(:destroy) }
+  # Validation tests
+  # ensure columns title and created_by are present before saving
+  it { should validate_presence_of(:title) }
+  it { should validate_presence_of(:created_by) }
+end