Change "_filename" to "_identifier" for carrierwave

app/models/design/stylesheet.rb

@@ -11,14 +11,14 @@ class Stylesheet < DesignFile
     content.scan(/(?<=url)(.*?)(?=\))/){
       css_name = $1.gsub(' ','').gsub('(','')
       name = File.basename(css_name).gsub(/[\\\"]/, '')
-      file_name = images.detect{ |i| i.file_filename.eql?(name) }.file_url rescue nil
+      file_name = images.detect{ |i| i.file_identifier.eql?(name) }.file_url rescue nil
       names << [css_name, file_name]
     }
     names.each do |name|
       content.gsub!(name[0], name[1]) if name[1]
     end
     Dir.mktmpdir('f_path') { |dir|
-      orig_file_name = self.file_filename
+      orig_file_name = self.file_identifier
       
       temp_file = File.new(dir + '/' + orig_file_name, 'w+')
       temp_file.write orig_content.force_encoding("UTF-8")