redmine/db/migrate/20091017212227_add_missing_indexes_to_workflows.rb

class AddMissingIndexesToWorkflows < ActiveRecord::Migration[4.2]
  def self.up
    add_index :workflows, :old_status_id
    add_index :workflows, :role_id
    add_index :workflows, :new_status_id
  end

  def self.down
    remove_index :workflows, :old_status_id
    remove_index :workflows, :role_id
    remove_index :workflows, :new_status_id
  end
end