Add together index for book.filename and book.path

    genres = models.ManyToManyField('Genre', through='bgenre')

    series = models.ManyToManyField('Series', through='bseries')

    class Meta:

        index_together = [

            ["filename", "path"],

        ]    

class Catalog(models.Model):

    parent = models.ForeignKey('self', null=True, db_index=True)

    cat_name = models.CharField(max_length=SIZE_CAT_CATNAME, db_index=True)