One of the retail tech start-ups from the inaugural class of the Target + Techstars retail accelerator program is expanding.

Branch Messenger, a mobile app that lets hourly workers easily swap shifts, view schedules and message one another, has raised $6.8 million in a Series A funding round. This brings the company’s total funding to more than $10 million, according to The Star Tribune, and makes Branch Messenger the most successful start-up…