# File ../lib/roller.rb, line 501
    def self.find_config_file(filename)
      filename += EXT_CONFIG if File.extname(filename).empty?
      # Check CWD then check default location.
      default_file = File.expand_path(File.join(DEFAULT_CONFIG_DIR, filename))
      
      if File.exist? filename
        return filename
      elsif File.exist? default_file
        return default_file
      else
        puts "Config file for replacement, '#{filename}', not found."
        return nil
      end
    end