A roadie is a drink you bring disguised in some sort of bottle. Usually a soda bottle filled some sort of liquor, (e.g. Sprite/Vodka, or Diet Coke/Whiskey). Whatever your drink of choice mixed in a common drink bottle. Hence, you can take it on the road with you. Roadie
"Did you bring the roadies for the hike bro"?
"Is that a Sprite or a roadie"?
"Hurry, grab the dogs and the roadies".