feat: Add Platform APIs (#1456)

spec/models/platform_app_permissible_spec.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe PlatformAppPermissible do
+  let!(:platform_app_permissible) { create(:platform_app_permissible) }
+
+  context 'with validations' do
+    it { is_expected.to validate_presence_of(:platform_app) }
+  end
+
+  context 'with associations' do
+    it { is_expected.to belong_to(:platform_app) }
+    it { is_expected.to belong_to(:permissible) }
+  end
+
+  describe 'with factories' do
+    it { expect(platform_app_permissible).present? }
+  end
+end