helpers.rb

def method_missing(method, *args)
  if method.to_s =~ /^flash_(.*)/
    type = case $1
    when 'error'
      :errors
    when 'warning'
      :warning
    when 'notice'
      :notices
    end
    flash(args.first, type)
  else
    super(method, *args)
  end
end

def flash(m, type)
  session[type] ||= []
  session[type] += m.errors
end

def flash_messages
  out = session.inspect
  session.delete(:errors)
  session.delete(:warning)
  session.delete(:notices)
  out
end