factoryman_demo_models.py

class Charity(models.Model):
    name = models.CharField(max_length=50, unique=True)
    webpage = models.URLField(unique=True)
    
    def __str__(self):
        return self.name
    
    
class Volunteer(models.Model):
    charity = models.ForeignKey(Charity, on_delete=models.PROTECT)
    name = models.CharField(max_length=50)
    email = models.EmailField(unique=True)

    def __str__(self):
        return self.name
    
        
class Project(models.Model):
    director = models.ForeignKey(Volunteer, on_delete=models.PROTECT)
    name = models.CharField(max_length=50)
    deadline = models.DateField()

    def __str__(self):
        return self.name