def complete_percentage_in(lang)
      if self.keys.blank?
        100
      else
        accepted_keys = accepted_keys(lang)
        100 * accepted_keys.count / self.keys.count
      end
    end
def complete_percentage_in(lang)
      if self.keys.blank?
        100
      else
        accepted_keys = accepted_keys(lang)
        100 * accepted_keys.count / self.keys.count
      end
    end
gets how much complete translation of category is in a certain language