A roadie is an individual who travels to gigs with a band and assists with setup and organization - most commonly girls (men traveling with the band are usually referred to as techies). You usually see them selling the tickets or refreshments, and/or sitting at a soundboard or helping the other bands during the show.
Roadies are sometimes mistaken for groupies, but there is a major difference. A groupie’s main goal is to sleep with the band whereas a roadie’s main goal is to insure the show runs smoothly and everyone in the band has their equipment set up and is ready. Occasionally they are paid.
Roadies are predominantly long time friends of the band and may even have had previous relationships with a band member. Sometimes they may be the girlfriend of a band member, but they are no longer considered roadies.
You know that band Cyrens from Troup? Well they just made Anna their roadie because they needed another person to help set up and run their gigs. It's fortunate her and Tiffany get along well; they will both make sure everything runs smoothly.