Upgrade issue with classification

@meidanis points out that his upgrade failed following !627 (merged):

Hi Guys! That's great! You created a field to allow administrators to sort the analysis configs in a custom order, instead of alphabetical order. At least that's what I understood with my so-so- French reading the comment to merge request !627 (merged) (merged).

This, however, posed a problem for me. My database doesn't have this field. So, I guess I'll have to do the procedure under "Migrating data" in the documentation, re-create a Vidjil installation from scratch, and, when I load back my database, the field will be there, and the vidjil_utils.py script will take care of initializing the classification field.

Is that it? I'll be glad to do it. Just confirm that this is indeed the process. And I guess I will have to do that every time the database changes.