add project_settings (Project#settings)

app/models/project.rb

@@ -232,6 +232,14 @@ class Project < ActiveRecord::Base
 
   has_many :project_badges, class_name: 'ProjectBadge'
 
+  has_one :settings, -> (project) {
+    query = where(project_id: project)
+    query.presence || begin
+      ProjectSettings.create(project_id: project.id)
+      query
+    end
+  }, class_name: 'ProjectSettings'
+
   accepts_nested_attributes_for :variables, allow_destroy: true
   accepts_nested_attributes_for :project_feature, update_only: true
   accepts_nested_attributes_for :import_data

app/models/project_settings.rb

+class ProjectSettings < ActiveRecord::Base
+  belongs_to :project
+end

db/migrate/20171030155459_create_project_settings.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class CreateProjectSettings < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def change
+    create_table :project_settings do |t|
+      t.references :project, index: true, foreign_key: { on_delete: :cascade }
+    end
+  end
+end

db/schema.rb

@@ -1504,6 +1504,12 @@ ActiveRecord::Schema.define(version: 20180418053107) do
 
   add_index "project_import_data", ["project_id"], name: "index_project_import_data_on_project_id", using: :btree
 
+  create_table "project_settings", force: :cascade do |t|
+    t.integer "project_id"
+  end
+
+  add_index "project_settings", ["project_id"], name: "index_project_settings_on_project_id", using: :btree
+
   create_table "project_statistics", force: :cascade do |t|
     t.integer "project_id", null: false
     t.integer "namespace_id", null: false
@@ -2185,6 +2191,7 @@ ActiveRecord::Schema.define(version: 20180418053107) do
   add_foreign_key "project_features", "projects", name: "fk_18513d9b92", on_delete: :cascade
   add_foreign_key "project_group_links", "projects", name: "fk_daa8cee94c", on_delete: :cascade
   add_foreign_key "project_import_data", "projects", name: "fk_ffb9ee3a10", on_delete: :cascade
+  add_foreign_key "project_settings", "projects", on_delete: :cascade
   add_foreign_key "project_statistics", "projects", on_delete: :cascade
   add_foreign_key "protected_branch_merge_access_levels", "protected_branches", name: "fk_8a3072ccb3", on_delete: :cascade
   add_foreign_key "protected_branch_push_access_levels", "protected_branches", name: "fk_9ffc86a3d9", on_delete: :cascade

spec/factories/project_settings.rb

+FactoryBot.define do
+  factory :project_settings do
+    project
+  end
+end

spec/models/project_spec.rb

@@ -115,6 +115,26 @@ describe Project do
         expect(subject.boards.size).to eq 1
       end
     end
+
+    describe '#settings' do
+      it 'creates lazily a settings record when the project does not have one associated' do
+        project = create :project
+        expect(ProjectSettings.count).to eq 0
+
+        expect(project.settings).to be_a ProjectSettings
+
+        expect(ProjectSettings.count).to eq 1
+      end
+
+      it 'returns the associated record when the project has one associated' do
+        project = create :project, settings: create(:project_settings)
+        expect(ProjectSettings.count).to eq 1
+
+        expect(project.settings).to be_a ProjectSettings
+
+        expect(ProjectSettings.count).to eq 1
+      end
+    end
   end
 
   describe 'modules' do