wrong number of arguments (3 for 2) for when ".csv" then Roo::Csv.new(file.path, nil, :ignore)

gistfile1.rb

class Product < ActiveRecord::Base
  require 'roo'
  validates_presence_of :price
  
  def self.to_csv(options = {})
    CSV.generate(options) do |csv|
      csv << column_names
      all.each do |product|
        csv << product.attributes.values_at(*column_names)
      end
    end
  end
  
  def self.import(file)
    spreadsheet = open_spreadsheet(file)
    header = spreadsheet.row(1)
    (2..spreadsheet.last_row).each do |i|
      row = Hash[[header, spreadsheet.row(i)].transpose]
      product = find_by_id(row["id"]) || new
      product.attributes = row.to_hash.slice(*accessible_attributes)
      product.save!
    end
  end

  def self.open_spreadsheet(file)
    case File.extname(file.original_filename)
    when ".csv" then Roo::Csv.new(file.path, nil, :ignore)
    when ".xls" then Roo::Excel.new(file.path, nil, :ignore)
    when ".xlsx" then Roo::Excelx.new(file.path, nil, :ignore)
    else raise "Unknown file type: #{file.original_filename}"
    end
  end
end

Importing Excel Spreadsheets using Roo

Limitation has mentioned.
http://railscasts.com/episodes/396-importing-csv-and-excel?view=asciicast
Read below lines from above link...
" This works. The list now contains the new products from the Excel document. One issue with this solution is that it doesn’t like to import any files that we export from our application: an exception is raised when we try it. Files generated by Excel seem to import without any problems, however. "