Challenge 1: A Comment Migration — Solution

Command:
$ rails generate migration CreateComments post_id:integer body:text author_name:string

Generated migration file:
# db/migrate/20260102000000_create_comments.rb
class CreateComments < ActiveRecord::Migration[7.1]
  def change
    create_table :comments do |t|
      t.integer :post_id
      t.text    :body
      t.string  :author_name
      t.timestamps
    end
  end
end

Resulting db/schema.rb entry (after `rails db:migrate`):
  create_table "comments" do |t|
    t.integer  "post_id"
    t.text     "body"
    t.string   "author_name"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

=begin
Notes:
- t.timestamps in the migration is what adds both created_at and
  updated_at to the schema automatically -- it's not something typed
  separately for each column, just one line covering both.
- post_id is defined as a plain integer column here -- the actual
  relationship to Post (making it a real foreign key Active Record
  understands) is what the next chapter's belongs_to association adds on
  top of this raw column.
- db/schema.rb is never edited directly -- it's entirely regenerated by
  Rails after rails db:migrate runs, always reflecting the combined result
  of every migration that has been applied so far.
=end