rails-migration | use generate and active_record | Application Framework library

I am currently migrating from Paperclip to Active Storage using this tutorial, as well as referencing the official guide.

Current roadblock is the rake task for migrating my assets.

This is the content of my lib/tasks/migrate_paperclip_assets.rake file:

I have a column named duration in a table named time_entries in a PostgreSQL database connected to a new Rails app. It is currently formatted to be time data, but I want it to be an integer. (Specifically, I'm going for a smallint column because it will be an amount of minutes not exceeding one day i.e. 1440.)

First, I tried:

I'm trying to remove an old model etc., that I had created by scaffolding several migrations past. So I followed the advice in this thread and ran a drop_table migration and the rails d scaffold Modelname command (maybe I did that first, not sure anymore).

As far as I can tell that removed the table and all the other files that had been created by the scaffolding, but my issue is that the schema.rb still includes the table! I've read here that I could probably fix this issue by running rails db:drop db:create db:migrate, but I was wondering if there is a way to fix schema.rb without resetting the database completely? (Unfortunately I started populating my db by console while I was adding parts to my app instead of writing a proper seed file.)

I have a column/foreign key, resolver_id, that I want to be able to have null values (ie: Rails Migration to make a column null => true). Let's say I have the following line in my migration: