Update documentation

README.md

@@ -29,15 +29,22 @@ If you just want to list the files that porto would change vanity import, run:
 ```bash
 porto -l path/to/library
 ```
+## Inclusion/exclusion rules
 
-If you want to ignore files (e.g. proto generated files), pass the `--skip-files` flag:
+`porto` skips autogenerated, internal, third party and vendored files by default. You can customize what files get included using some flags:
+
+- If you want to ignore files (e.g. proto generated files), pass the `--skip-files` flag:
 
 ```bash
 porto --skip-files ".*\\.pb\\.go$" path/to/library
 ```
+- If you want to ignore directories (e.g. tooling directories), pass the `--skip-dirs` flag:
 
-If you want to include `internal` folders too
+```bash
+porto --skip-dirs "^tools$" path/to/library
+```
+- If you want to include `internal` folders and directories skipped by default:
 
 ```bash
-porto --include-internal path/to/library
+porto --include-internal --skip-dirs-use-default=false path/to/library
 ```