Make the following changes:
# features/support/database_cleaner.rb
# remove
FileUtils.rm_rf Dir['assets/img/usr/test/**/*.jpg']
# add
FileUtils.rm_rf Dir['pdf/test/**/*.jpg']$ touch pdf/production/.keep# .gitignore
.env
pdf/test/*
.DS_Store
When you are done, make sure to add new files and commit your changes.
$ git add .
$ git commit -am "fix for missing folder on heroku"
$ git push origin master
$ git push heroku master