# frozen_string_literal:true class AddSlugToTrainings < ActiveRecord::Migration[4.2] def up add_column :trainings, :slug, :string add_index :trainings, :slug, unique: true Training.all.each do |t| slug = t.send(:set_slug) || t.slug t.update_columns(slug: slug) end end def down remove_column :trainings, :slug, :string remove_index :trainings, :slug end end