fix parameter name
diff --git a/migration/README.md b/migration/README.md
index a9a11ea..32b0e65 100644
--- a/migration/README.md
+++ b/migration/README.md
@@ -69,10 +69,10 @@
This also map all Jira username to GitHub account (or Jira full name, if the corresponding GitHub account is not available) if the account mapping is given in `mapping-data/account-map.csv` and `mapping-data/jira-users.csv`.
-Optionally, you can pass `--num_workers` option to specifiy the number of worker processes (the default value is `1`).
+Optionally, you can pass `--num-workers` option to specifiy the number of worker processes (the default value is `1`).
```
-(.venv) migration $ python src/jira2github_import.py --min 10500 --max 10510 --num_workers 2
+(.venv) migration $ python src/jira2github_import.py --min 10500 --max 10510 --num-workers 2
[2022-07-16 09:32:42,288] INFO:jira2github_import: Converting Jira issues to GitHub issues in /mnt/hdd/repo/lucene-jira-archive/migration/github-import-data. num_workers=2
[2022-07-16 09:32:48,286] INFO:jira2github_import: Done.
