hstore_serializer.rb

module HstoreSerializer
  extend ActiveSupport::Concern

  module ClassMethods    def hstore_array(*attributes)
      attributes.each do |attr|
        define_method "#{attr}=" do |values|
          self[attr] = convert_to_hash(values)
        end 

        define_method attr do
          self[attr].try(:keys) || []
        end 

      end 
    end 
  end 

  private

  def convert_to_hash(values)
    values.select(&:present?).inject({}) {|hash, s| hash.merge({ s => true}) }
  end 

end