Backport `add_default_project_creation_setting` to CE

db/migrate/20180115094742_add_default_project_creation_setting.rb

+class AddDefaultProjectCreationSetting < ActiveRecord::Migration[4.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_column_with_default(:application_settings, :default_project_creation, :integer, default: 2)
+  end
+
+  def down
+    remove_column(:application_settings, :default_project_creation)
+  end
+end

db/migrate/20190311132500_add_default_project_creation_application_setting.rb

-# frozen_string_literal: true
-
-# See http://doc.gitlab.com/ce/development/migration_style_guide.html
-# for more information on how to write migrations for GitLab.
-
-class AddDefaultProjectCreationApplicationSetting < ActiveRecord::Migration[5.0]
-  include Gitlab::Database::MigrationHelpers
-
-  DOWNTIME = false
-
-  def up
-    unless column_exists?(:application_settings, :default_project_creation)
-      add_column(:application_settings, :default_project_creation, :integer, default: 2, null: false)
-    end
-  end
-
-  def down
-    if column_exists?(:application_settings, :default_project_creation)
-      remove_column(:application_settings, :default_project_creation)
-    end
-  end
-end