Statesboro city employees, among them desk jockeys and maintenance workers and a cop literally walking a beat, are keeping track of every step they take as part of the city’s Fit By ’15 Health and Wellness Challenge. Sixty-three of the city’s more than 300 employees signed up for the pilot program, which began July 1 and extends through December. Each was assigned a Fitbit Zip, a watch-size wireless activity tracker worn at the waist.