title: Writing the xlsx file using RubyXL taking very long time with large number of cells
body: <p>I am Using RubyXL gem in my rails application to generate the workbook with 4-5 sheets.We are generating excel with large number of cells(more than 5000(146*26)). It takes more than 20 minutes to write that file and consume a lot of memory. One of the sheet is having dynamic data which has some styles like border back ground color, font color, bold text etc.I am using this code snippet. </p>
  
  <pre><code>workbook = RubyXL::Workbook.new()
  sheet = workbook.worksheets[0]
  cell = sheet.add_cell(row, col, text)
  cell.change_fill('#fff')
  cell.change_font_color('#000')
  cell.change_font_bold(true)
  </code></pre>
  
  <p>I tried to reduce the time by removing some style like borders by which it reduce some time in writing but it still taking long time. So I've removed the remaining styling mentioned above. After which it is now taking 1 minute approx.</p>
  
  <p>can you please suggest me the way to apply the styling to the cells so that it will take less time and will not affect the performance.</p>
  
  <p>I will be happy to answer any question/query regarding this or if I miss anything.</p>