Update README.md

README.md

@@ -23,8 +23,12 @@ schemaToErd('./schema_samples/sakila-schema.sql');
 
 ### Sample Schema file
 
-1. [Employees Sample Database](https://dev.mysql.com/doc/employee/en/) - https://github.com/datacharmer/test_db
-2. [MySQL Sample Database](https://www.mysqltutorial.org/mysql-sample-database.aspx) - https://www.mysqltutorial.org/wp-content/uploads/2018/03/mysqlsampledatabase.zip
-3. https://github.com/ronaldbradford/schema
+1. [Sakila Sample Database](https://dev.mysql.com/doc/index-other.html)
+2. [Employees Sample Database](https://dev.mysql.com/doc/employee/en/) - https://github.com/datacharmer/test_db
+3. [MySQL Sample Database](https://www.mysqltutorial.org/mysql-sample-database.aspx) - https://www.mysqltutorial.org/wp-content/uploads/2018/03/mysqlsampledatabase.zip
+4. https://github.com/ronaldbradford/schema
 
 ![sakila-schema.puml](puml_examples/sakila-schema.png)
+
+### Contribute
+If an error occurs during use, please [open a new issue](https://github.com/youngkiu/schema-to-erd/issues) with the schema.sql file.