From https://stackoverflow.com/questions/22215394/does-require-tree-require-files-inside-vendor-assets-and-lib-assets-rail
# Put this in app/assets/stylesheets/application.css.scss if you wanna reference css from vendor or lib # Do the same for javascript files //= require_tree ../../../vendor/assets/javascripts/. //= require_tree ../../../lib/assets/javascripts/.