feat(salesforce): Add integration models (#2787)

## Roadmap Task

👉
https://getlago.canny.io/feature-requests/p/sync-lago-customers-with-salesforce

## Context

We need to be able to create a Salesforce integration in Lago and sync
Lago customers to Salesforce using this integration details.

## Description

This PR adds Salesforce integration model and specs.

app/models/integrations/base_integration.rb

@@ -40,6 +40,8 @@ def self.integration_type(type)
         'Integrations::XeroIntegration'
       when 'hubspot'
         'Integrations::HubspotIntegration'
+      when 'salesforce'
+        'Integrations::SalesforceIntegration'
       else
         raise(NotImplementedError)
       end

app/models/integrations/salesforce_integration.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module Integrations
+  class SalesforceIntegration < BaseIntegration
+    validates :instance_id, presence: true
+    validates :code, inclusion: {in: %w[salesforce]}
+
+    settings_accessors :instance_id
+  end
+end
+
+# == Schema Information
+#
+# Table name: integrations
+#
+#  id              :uuid             not null, primary key
+#  code            :string           not null
+#  name            :string           not null
+#  secrets         :string
+#  settings        :jsonb            not null
+#  type            :string           not null
+#  created_at      :datetime         not null
+#  updated_at      :datetime         not null
+#  organization_id :uuid             not null
+#
+# Indexes
+#
+#  index_integrations_on_code_and_organization_id  (code,organization_id) UNIQUE
+#  index_integrations_on_organization_id           (organization_id)
+#
+# Foreign Keys
+#
+#  fk_rails_...  (organization_id => organizations.id)
+#

app/models/organization.rb

@@ -46,6 +46,7 @@ class Organization < ApplicationRecord
   has_many :hubspot_integrations, class_name: "Integrations::HubspotIntegration"
   has_many :netsuite_integrations, class_name: "Integrations::NetsuiteIntegration"
   has_many :xero_integrations, class_name: "Integrations::XeroIntegration"
+  has_one :salesforce_integration, class_name: "Integrations::SalesforceIntegration"
 
   has_one :applied_dunning_campaign, -> { where(applied_to_organization: true) }, class_name: "DunningCampaign"
 
@@ -58,7 +59,9 @@ class Organization < ApplicationRecord
     :per_organization
   ].freeze
 
-  INTEGRATIONS = %w[netsuite okta anrok xero progressive_billing hubspot auto_dunning revenue_analytics].freeze
+  INTEGRATIONS = %w[
+    netsuite okta anrok xero progressive_billing hubspot auto_dunning revenue_analytics salesforce
+  ].freeze
   PREMIUM_INTEGRATIONS = INTEGRATIONS - %w[anrok]
 
   enum document_numbering: DOCUMENT_NUMBERINGS

spec/factories/integrations.rb

@@ -77,4 +77,15 @@
       {connection_id: SecureRandom.uuid}.to_json
     end
   end
+
+  factory :salesforce_integration, class: 'Integrations::SalesforceIntegration' do
+    organization
+    type { 'Integrations::SalesforceIntegration' }
+    code { 'salesforce' }
+    name { 'Salesforce Integration' }
+
+    settings do
+      {instance_id: SecureRandom.uuid}
+    end
+  end
 end

spec/models/integrations/base_integration_spec.rb

@@ -95,6 +95,12 @@
       end
     end
 
+    context 'when type is salesforce' do
+      it 'returns the correct class name' do
+        expect(described_class.integration_type('salesforce')).to eq('Integrations::SalesforceIntegration')
+      end
+    end
+
     context 'when type is unknown' do
       it 'raises a NotImplementedError' do
         expect { described_class.integration_type('unknown') }.to raise_error(NotImplementedError)

spec/models/integrations/salesforce_integration_spec.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Integrations::SalesforceIntegration, type: :model do
+  subject(:salesforce_integration) { build(:salesforce_integration) }
+
+  it { is_expected.to validate_presence_of(:name) }
+  it { is_expected.to validate_presence_of(:instance_id) }
+  it { is_expected.to validate_inclusion_of(:code).in_array(%w[salesforce]) }
+
+  describe 'validations' do
+    it 'validates uniqueness of the code' do
+      expect(salesforce_integration).to validate_uniqueness_of(:code).scoped_to(:organization_id)
+    end
+  end
+
+  describe '#instance_id' do
+    it 'assigns and retrieve a setting' do
+      salesforce_integration.instance_id = 'instance_id_1'
+      expect(salesforce_integration.instance_id).to eq('instance_id_1')
+    end
+  end
+
+  describe '#code' do
+    it 'returns salesforce' do
+      expect(salesforce_integration.code).to eq('salesforce')
+    end
+  end
+end

spec/models/organization_spec.rb

@@ -22,6 +22,7 @@
   it { is_expected.to have_many(:hubspot_integrations) }
   it { is_expected.to have_many(:netsuite_integrations) }
   it { is_expected.to have_many(:xero_integrations) }
+  it { is_expected.to have_one(:salesforce_integration) }
   it { is_expected.to have_many(:data_exports) }
   it { is_expected.to have_many(:dunning_campaigns) }
   it { is_expected.to have_many(:daily_usages) }