Remove factories from AddHeadPipelineForEachMergeRequest spec

spec/migrations/add_head_pipeline_for_each_merge_request_spec.rb

 require 'spec_helper'
 require Rails.root.join('db', 'post_migrate', '20170508170547_add_head_pipeline_for_each_merge_request.rb')
 
-describe AddHeadPipelineForEachMergeRequest, :delete do
-  include ProjectForksHelper
-
+describe AddHeadPipelineForEachMergeRequest, :migration do
   let(:migration) { described_class.new }
 
-  let!(:project) { create(:project) } # rubocop:disable RSpec/FactoriesInMigrationSpecs
-  let!(:other_project) { fork_project(project) }
+  let!(:project) { table(:projects).create! }
+  let!(:other_project) { table(:projects).create! }
 
-  let!(:pipeline_1) { create(:ci_pipeline, project: project, ref: "branch_1") } # rubocop:disable RSpec/FactoriesInMigrationSpecs
-  let!(:pipeline_2) { create(:ci_pipeline, project: other_project, ref: "branch_1") } # rubocop:disable RSpec/FactoriesInMigrationSpecs
-  let!(:pipeline_3) { create(:ci_pipeline, project: other_project, ref: "branch_1") } # rubocop:disable RSpec/FactoriesInMigrationSpecs
-  let!(:pipeline_4) { create(:ci_pipeline, project: project, ref: "branch_2") } # rubocop:disable RSpec/FactoriesInMigrationSpecs
+  let!(:pipeline_1) { table(:ci_pipelines).create!(project_id: project.id, ref: "branch_1") }
+  let!(:pipeline_2) { table(:ci_pipelines).create!(project_id: other_project.id, ref: "branch_1") }
+  let!(:pipeline_3) { table(:ci_pipelines).create!(project_id: other_project.id, ref: "branch_1") }
+  let!(:pipeline_4) { table(:ci_pipelines).create!(project_id: project.id, ref: "branch_2") }
 
-  let!(:mr_1) { create(:merge_request, source_project: project, target_project: project, source_branch: "branch_1", target_branch: "target_1") } # rubocop:disable RSpec/FactoriesInMigrationSpecs
-  let!(:mr_2) { create(:merge_request, source_project: other_project, target_project: project, source_branch: "branch_1", target_branch: "target_2") } # rubocop:disable RSpec/FactoriesInMigrationSpecs
-  let!(:mr_3) { create(:merge_request, source_project: project, target_project: project, source_branch: "branch_2", target_branch: "master") } # rubocop:disable RSpec/FactoriesInMigrationSpecs
-  let!(:mr_4) { create(:merge_request, source_project: project, target_project: project, source_branch: "branch_3", target_branch: "master") } # rubocop:disable RSpec/FactoriesInMigrationSpecs
+  let!(:mr_1) { table(:merge_requests).create!(source_project_id: project.id, target_project_id: project.id, source_branch: "branch_1", target_branch: "target_1") }
+  let!(:mr_2) { table(:merge_requests).create!(source_project_id: other_project.id, target_project_id: project.id, source_branch: "branch_1", target_branch: "target_2") }
+  let!(:mr_3) { table(:merge_requests).create!(source_project_id: project.id, target_project_id: project.id, source_branch: "branch_2", target_branch: "master") }
+  let!(:mr_4) { table(:merge_requests).create!(source_project_id: project.id, target_project_id: project.id, source_branch: "branch_3", target_branch: "master") }
 
   context "#up" do
     context "when source_project and source_branch of pipeline are the same of merge request" do