install.rb in cssbundling-rails-1.1.1

- old
+ new

@@ -2,10 +2,10 @@
 copy_file "#{__dir__}/application.bulma.scss",
    "app/assets/stylesheets/application.bulma.scss"
 run "yarn add sass bulma"
 
 say "Add build:css script"
-build_script = "sass ./app/assets/stylesheets/application.bulma.scss ./app/assets/builds/application.css --no-source-map --load-path=node_modules"
+build_script = "sass ./app/assets/stylesheets/application.bulma.scss:./app/assets/builds/application.css --no-source-map --load-path=node_modules"
 
 if (`npx -v`.to_f < 7.1 rescue "Missing")
   say %(Add "scripts": { "build:css": "#{build_script}" } to your package.json), :red
 else
   run %(npm set-script build:css "#{build_script}")