Attaches the specified object to the specified index.
clouddirectory_attach_to_index(DirectoryArn, IndexReference,
  TargetReference)[required] The Amazon Resource Name (ARN) of the directory where the object and index exist.
[required] A reference to the index that you are attaching the object to.
[required] A reference to the object that you are attaching to the index.
svc$attach_to_index(
  DirectoryArn = "string",
  IndexReference = list(
    Selector = "string"
  ),
  TargetReference = list(
    Selector = "string"
  )
)