class Rails::Railtie::Configuration

def method_missing(name, *args, &blk)
  if name.end_with?("=")
    key = name[0..-2].to_sym
    if actual_method?(key)
      raise NoMethodError.new("Cannot assign to `#{key}`, it is a configuration method")
    end
    @@options[key] = args.first
  elsif @@options.key?(name)
    @@options[name]
  else
    super
  end
end