Override default primary key Raw - Solution

create_content_units.rb

class CreateContentUnits < ActiveRecord::Migration
  def up
    create_table :content_units, id: false do |t|
      t.boolean :active, default: false
    end
    execute 'ALTER TABLE content_units ADD guoid BIGINT(20) PRIMARY KEY AUTO_INCREMENT FIRST;'
  end

  def down
    drop_table :guoids
  end
end