GOMA, Congo — In a makeshift nightclub in the hull of the overnight ferry from Goma to Bukavu, a handful of teenage boys are trying out some new moves. Some land, some don’t. When they don’t, the elderly man on the bench next to us nudges us and rolls his eyes, amused. The DJ, who has so far been playing the usual Afrobeats hits and Congolese rumba, whips out a more unexpected Communist crossover: the Russian Internationale — the pre-1944 Soviet national anthem — mixed with a Congolese beat. People immediately pack the dancefloor. Here in eastern Congo, enthusiasm is palpable for the “Russians…