class Brand(models.Model):
    """Производители авто, такие как BMW, Audi, etc"""

class Model(models.Model):
    """Модельный ряд определенного производителя"""
    brand = models.ForeignKey(Brand)

class Engine(models.Model):
    """Модификации двигателей"""
    brand = models.ForeignKey(Model)

class BrandAdmin(admin.ModelAdmin):
    list_display = ('name', )

class ModelAdmin(admin.ModelAdmin):
    list_display = ('name', 'fromYear', 'toYear')
    list_filter = ('brand', )

class EngineAdmin(admin.ModelAdmin):
    list_display = ('model', 'name', 'category', 'type', 'kind', 'capacity', 'power')
    list_filter = ('model', )

class Category(models.Model):
    title = models.CharField(max_length=255)
    parent = models.ForeignKey('self', blank=True, null=True)

class CategoryAdmin(admin.ModelAdmin):
    list_display = ('title','parent')
    search_fields = ['parent__title', 'title']
admin.site.register(Category, CategoryAdmin)