Issue import cell string using roo

Question

When I import an excel data file is saving format as number.

Excel example

|num_doc| |name|
  1234     CR7
  5678     Beckham
  9102     Bush

Controller client_controller.rb:

def import
  Client.import(params[:file])
end

Model client.rb

@errors = []
spreadsheet = open_spreadsheet(file)
  (2..spreadsheet.last_row).each do |i|
    column1 = spreadsheet.cell(i,'A').to_s  
    column2 = spreadsheet.cell(i,'B').to_s

    client = Client.new(:num_doc => column1,
                        :name => column2)

    if client.save
      # stuff to do on successful save 
    else
      client.errors.full_messages.each do |message|
        @errors << "Issue on line #{i}, <strong>column #{message}</strong>".html_safe
      end
    end
 end  
 @errors #  <- need to return the @errors array   
end  

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

When I import the excel file the column num_doc is saving adding number format and want to save the string value.

|num_doc|   |name|
1234.0      Cr7
5678.0      Beckham

I tried but is still saving as number.

 column1 = spreadsheet.cell(i,'A').to_s #to String

 :num_doc => column1.to_s  #to string