Update README.md

Added note to run script in case pipenv is not working for you.

Author: rebelbot

README.md

@@ -14,5 +14,5 @@ From root directory:
 1. Click on the **Link/Embed** link for the episode
 1. Copy the last number in the "Libsyn Directory URL"
 1. Add it to `_sitegen/directory_ids.csv` with the episode number in front.
-1. Run `pipenv run _sitegen/generate.py`
+1. Run `pipenv run _sitegen/generate.py` Note: if this isn't working for you, try using `python3 _sitegen/generate.py`
 1. Review changes with `git diff` or equivalent. Commit. Push.