class User(models.Model):
  username = models.CharField(max_length=20)
  password = models.CharField(max_length=36)
  crt_date = models.DateField(auto_now_add=True)
  groups = models.ManyToManyField('Group')


class Group(models.Model):
  name = models.CharField(max_length=20)
  admin = models.ForeignKey('User', on_delete=models.CASCADE)


class Task(models.Model):
  STATUS = (('TD', 'To do'), ('IP', 'In progress'), 'DN', 'Done')
  PRIORITY = (('LO', 'Low'), ('NO', 'Normal'), ('HI', 'High'), ('CR', 'Critical'))
  title = models.CharField(max_length=40)
  content = models.CharField(max_length=480)
  status = models.CharField(max_length=2, choices=STATUS, default='TD')
  priority = models.CharField(max_length=2, choices=PRIORITY, default='NO')
  project = models.ForeignKey('Project', on_delete=models.CASCADE)


class Project(models.Model):
  name = models.CharField(max_length=20)
  group = models.ForeignKey('Group', on_delete=models.CASCADE)