class Arena(models.Model):
exp_time = models.DateTimeField(...
win_count = models.PositiveIntegerField(default=0, ...
...
class ArenaUser(models.Model):
arena = models.ForeignKey(Arena,...
user = models.ForeignKey(User,...
...
class Arena(models.Model):
exp_time = models.DateTimeField(...
win_count = models.PositiveIntegerField(default=0, ...
users = models.ManyToManyField(User,...
...