Automatically add bootstrap sass theme with Drush
Download the patch into your Drupal 8 Bootstrap theme folder.
Apply the patch with the command:
patch -p1 < path/file.patch
Go to your sites/sitename folder or sites if you have only 1 website
Use Drush to create a new bootstrap sass subtheme with the command:
drush bsass [theme-name]
example:
drush bsass mynewtheme
This will setup the new theme with the name provided.