iServ is a company offering cleaning services for houses, buildings, and other types of property. The company employs many employees for different job roles such as administrator, cleaner, etc. Besides, the company also works with external vendors that provide other service types such as air-condition service, plumbing service, and installation service. The iServ owner wants to computerize their business to manage their services, vendors, customers, cleaners job scheduling, payments, etc. Vendors could register through a new system by indicating their service type, and rate