feat(plans): add model

app/models/plan.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Plan < ApplicationRecord
+  validates :name, :description, :amount, presence: true
+  validates :amount, numericality: true
+end

spec/factories/plans.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :plan do
+    name { Faker::Lorem.words(number: 4) }
+    description { Faker::Lorem.paragraph }
+    amount { Faker::Number.decimal(l_digits: 2, r_digits: 2) }
+  end
+end

spec/models/plans_spec.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Plan, type: :model do
+  let(:plan) { FactoryBot.build_stubbed(:plan) }
+
+  subject { plan }
+
+  describe 'attributes' do
+    it { is_expected.to respond_to(:name) }
+    it { is_expected.to respond_to(:description) }
+    it { is_expected.to respond_to(:amount) }
+    it { is_expected.to be_valid }
+  end
+
+  describe 'validations' do
+    it { is_expected.to validate_presence_of(:name) }
+    it { is_expected.to validate_presence_of(:description) }
+    it { is_expected.to validate_presence_of(:amount) }
+    it { is_expected.to allow_value(1235.123).for(:amount) }
+  end
+end