public/stylesheets/application.css: This will be our default css file. It does not have to be called application.css. We call it that because of the line stylesheetlinktag application in the layout. < stylesheetlinktag "request.hostwithport/assets/gettile" >.Rails will automatically detect it. Specify path. To include app/assets/stylesheets/gettile.css.scss and app/assets/stylesheets/subfolder/yourfile.css OR It takes the type of the link (:rss or :atom), a hash of options that are passed through to urlfor, and a hash of options for the tagThe stylesheetlinktag helper returns an HTML tag for each source provided.