Gakkyou Saiban Death Game

The only way to repent for this “crime” is death. When Manaka, a girl with a strong sense of justice, transfers to a new school, she finds out about a crazy rule in her class: everyone in the class is forced to join a chat room. Every time there's some conflict, a “class trial” is held there. The student who loses in the trial is made the target of fierce bullying from the next day. A story of love and hatred amongst young people.

(Source: Kurage Bunch, translated)