Cleanup structure.sql file after it is created

mysql_cleanup_task.rake

Rake::Task["db:structure:dump"].enhance do
  path = Rails.root.join('db', 'structure.sql')
  file = File.read(path)
  file.gsub!(/ AUTO_INCREMENT=\d*/, '')
  # remove all comment lines
  file.gsub!(/^--.*/,'')
  File.write(path, file)
end