Rails i18n nested translations with ActiveRecord backend

Question

I know that I can create nested translations in i18n dictionary. e.g.

en:
  bugs:
    index:
      new_label: "File a new bug"
      edit_label: "edit"
      delete_label: "delete"

It works perfect with simple YAML-files. But what will be if I want to use ActiveRecord as backend for i18n?

Smth like this

I18n.backend = I18n::Backend::ActiveRecord.new

I found some migration for this feature

class CreateTranslations < ActiveRecord::Migration
  def self.up
    create_table :translations do |t|
      t.string :locale
      t.string :key
      t.text   :value
      t.text   :interpolations
      t.boolean :is_proc, :default => false

      t.timestamps
    end
  end

  def self.down
    drop_table :translations
  end
end

How can I save nested translations in this case? Without it translation must be like

{ bugs: value, bugs_index: value, bugs_index_new_label: value, ... }

But in my opinion it's not nice solution...