gistfile1.rb

# This is the wrong was to do this. What if one of the order products fails?
def create
  @order = Order.new
  if @order.save
    for order in params[:order][:product_ids]
      OrderProducts.create(:order_id => @order.id, :product_id => Product.find(params[:id]).id)
    end
    flash[:notice] = "Thanks, your order will be completed shortly!"
    redirect_to :action => "index"
  else
    render :action => "new"
  end
end

# On save, this will save and validate all the order_products too
def create
  @order = Order.new
  for order in params[:order][:product_ids]
    @order.order_products.build(:product => Product.find(params[:id]))
  end
  if @order.save
    flash[:notice] = "Thanks, your order will be completed shortly!"
    redirect_to :action => "index"
  else
    render :action => "new"
  end
end