关闭应用程序时AndroidRTC致命错误

Question

  

我正在使用androidRTC，https://github.com/pchab/AndroidRTC

     

关闭时应用程序崩溃。此错误出现在日志中：

class Environment(models.Model):
    name = models.CharField(max_length=250)
    animals = models.ManyToManyField(Animal, through='AnimalList')

class Animal(models.Model):
    name = models.CharField(max_length=200)
    safe_around_david_cameron = models.BooleanField()

class AnimalList(models.Model):
    environment = models.ForeighKey(Environment)
    animal = models.ForeignKey(Animal)