The holiday shopping season is about to commence and Forsyth County retailers are ready for the crowds, thanks to some help from valuable seasonal employees. Old Navy on Market Place Boulevard in Cumming has added between 10 and 15 people to its staff. With 75 regular and seasonal employees, spokesman Derrick Smith said the store is “excited about the Thanksgiving holiday and some of the things we’re doing in order to enable us to hire more.”Smith said seasonal employment hiring began “the first or second week in October and that will last all the way through Christmas ... to the second or third week in January.”The clothing retailer is a popular place to work, largely because of two factors.