Kiel

@Daniele Deltodesco
Hi. I was just able to fix this. Heroku doesn't seem to mix well with Webpack as it tries to find bootstrap/scss/bootstrap in the app/assets/stylesheets folder. You have to point the import out of the folder to node_modules where Bootstrap stored in.

Make sure that your app/assets/stylesheets/application.css is renamed to application.css.scss and change @import "bootstrap/scss/bootstrap"; to @import "../../../node_modules/bootstrap/scss/bootstrap.scss";