add local dev tip comment

Author: stancl

docker-compose.yml

@@ -24,3 +24,5 @@ services:
         condition: service_healthy
     volumes:
       - ./src:/var/www/html
+      # When testing a local tenancy version, you can use a symlink in combination with:
+      # - ~/Projects/tenancy:/var/www/html/vendor/stancl/tenancy