Add service to create a new board for a project

app/services/boards/create_service.rb

+module Boards
+  class CreateService
+    def initialize(project)
+      @project = project
+    end
+
+    def execute
+      if project.board.present?
+        project.board
+      else
+        project.create_board
+      end
+    end
+
+    private
+
+    attr_reader :project
+  end
+end

spec/factories/projects.rb

@@ -83,4 +83,10 @@ FactoryGirl.define do
       )
     end
   end
+
+  factory :project_with_board, parent: :empty_project do
+    after(:create) do |project|
+      project.create_board
+    end
+  end
 end

spec/services/boards/create_service_spec.rb

+require 'spec_helper'
+
+describe Boards::CreateService, services: true do
+  describe '#execute' do
+    it 'creates a new board when project does not has one' do
+      project = create(:empty_project, board: nil)
+      service = described_class.new(project)
+
+      expect { service.execute }.to change(Board, :count).by(1)
+    end
+
+    it 'returns project board when project has one' do
+      project = create(:project_with_board)
+      service = described_class.new(project)
+
+      expect(service.execute).to eq project.board
+    end
+  end
+end