Django haystack how to setup lookup for intermediate models with foreign key?

Question

Django

Hello. For one of my projects, I'm adding a search for django haystack c solr.
There was a question how to search through foreign key.

# Модель по которой осуществляется поиск
class ItemModel(models.Model):
    name = models.CharField(max_length=255)
    
    
# Категория
class CategoryModel(models.Model):
    name = models.CharField(max_length=255)
    
    
# Связь между item и категорией
class ItemToCategoryModel(models.Model):
    item = models.ForeignKey('ItemModel')
    category = models.ForeignKey('CategoryModel')

How to build an index to search item by category?