class StrongController < ApplicationController def index logger.info(Hot::Constants) end def update logger.info 'parameters', strong_params redirect_to strong_path, notice: 'form is ok' end private def strong_params # params.require(:strong).permit [:name, :surname, { birth: {} }] # implicit: any fields inside bith params.require(:strong).permit [:name, :surname, { birth: %i[date location] }] # explicit end end