symfony2 dodanie indexu

AdvancedVerifyFieldBundle\Entity\AdvancedVerifyField:
    type:  entity
    repositoryClass: MultiStepFormBundle\Repository\MultiStepFormClientData\MultiStepFormClientDataRepository
    table: advanced_verify_field
    id :
        transaction_id :
            type: uuid
            generator:
                strategy: CUSTOM
            customIdGenerator:
                class: Ramsey\Uuid\Doctrine\UuidGenerator
    fields:
        searchHash:
            type: string
            nullable: false
            length: 32
        code:
            type: string
            nullable: false
            length: 16
        createdAt :
            type: datetime
            nullable: false
        confirmedAt :
            type: datetime
            nullable: true
        type:
            type: smallint
            nullable: false
        value:
            type: string
            nullable: false
            length: 255
    indexes:
        search_index:
          columns: [ searchHash ]