class Category(models.Model):
    id = models.IntegerField("id", primary_key=True)
    name = models.CharField("Наименование", max_length=150)

class Course(models.Model):
    category = models.ForeignKey(Category, verbose_name="Категория курса", on_delete=models.CASCADE)
    name = models.CharField("Название", max_length=150)