I’m assuming the migration isn’t working because it’s not able to convert the current values in the column to the new type.
You might want to do this in multiple migrations:
- A migration to create a new column with type
{:array, :string}and copy all the old column values to the new column as a list of strings. - A migration to delete the old column.
- A migration to rename the new column to be the name of the deleted column.
