Added more info about CLI arguments

Author: RolandBende

README.md

@@ -8,7 +8,7 @@ Migrations are like version control for your database, allowing you to define an
 
 - Google Cloud Project with enabled billing
 - Enabled Google Cloud BigQuery API
-- Google Cloud Service Account
+- Google Cloud Service Account JSON file
 
 ## Getting Started
 
@@ -45,6 +45,15 @@ your-project
 └── ...
 ```
 
+You can use different folder names but in that case you must specify them with command arguments:
+
+|argument             |description                                                |
+|---------------------|-----------------------------------------------------------|              
+|--gcp-sa-json-dir    |Name of the service account JSON file directory (optional) |
+|--gcp-sa-json-fname  |Name of the service account JSON file (optional)           |
+|--migrations-dir     |Name of the migrations directory (optional)                |
+
+
 ## Running migrations
 
 > **IMPORTANT!**