The index assignment UI uses the same table-form pattern as the index
UI. There is currently no control over deleting indices when an index
assignment exists on that index.
Previously, articles written by Ersatz Scrivener were represented in
the data model by having a NULL character id. This had several awkward
consequences, such as therebeing no real way to distinguish Ersatz
articles from different players without doubling up on foreign keys
whenever there was a character reference, because there would need to
be a user reference as well.
Using a flag on the article itself is a much cleaner solution. There is
no longer a need to have both character and user FKs. Ersatz-ness is
still a special case, but one easily tracked on articles without
changing how basic objects of the game relate to each other. Ersatz
articles can be treated differently in the stats just as easily while
still being subject to character-specific rules like index assignments.
Unlike the player and setup settings, the form here has a variable
number of inputs, so we use a blank row to allow expanding the index
set and allow deleting by clearing out the index type
