Merge pull request #481 from antograssiot/swager-yaml-export

Document the yaml option in swagger export command

Author: dunglas

core/swagger.md

@@ -284,6 +284,9 @@ You can also dump your current Swagger documentation using the provided command:
 ```
 $ docker-compose exec php bin/console api:swagger:export
 # Swagger documentation in JSON format...
+
+$ docker-compose exec php bin/console api:swagger:export --yaml 
+# Swagger documentation in YAML format... 
 ```
 
 ## Overriding the UI Template