Single Database Configuration steps:
rails g migration singlify_solid_cable (or whatever you want to call it)
Copy the contents of db/cable_schema.rb into the migration. Mine ended up looking like this:
class SinglifySolidCable < ActiveRecord::Migration[8.0]
def change
create_table "solid_cable_messages", force: :cascade do |t|
t.binary "channel", limit: 1024, null: false