This change should have no user impact.
I created a column in 8d707a9c74. I wanted
it to be a `BLOB`. I succeeded because [SQLite chooses `BLOB` by
default][0], but I wish I had been explicit.
I *could've* updated the migration, but didn't want to make a mistake
and cause divergent migrations. Instead, I added a comment.
I also updated a test.
[0]: https://www.sqlite.org/datatype3.html#determination_of_column_affinity
