rails g modelコマンドを実行しモデルとマイグレーションファイルを作成し、作成したマイグレーションファイルに追加したいカラムを追記し、rails g migrationコマンドを実行しました。
下記のコードは、作成したマイグレーションファイルにカラムを追加する記述と、ターミナルでのrails g migrationコマンドを実行したものです。

class CreateArticles < ActiveRecord::Migration[6.0]
def change
create_table :articles do |t|
t.date :dating
t.string :title
t.text :text

  t.timestamps
end

end
end

rooter:portfolio apple$ rails g migration
Running via Spring preloader in process 6990
Usage:
rails generate migration NAME [field[:type][:index] field[:type][:index]] [options]

Options:
[--skip-namespace], [--no-skip-namespace] # Skip namespace (affects only isolated applications)
-o, --orm=NAME # ORM to be invoked

Default: active_record

ActiveRecord options:
[--primary-key-type=PRIMARY_KEY_TYPE] # The type for primary key
--db, [--database=DATABASE] # The database for your migration. By default, the current environment's primary database is used.

Runtime options:
-f, [--force] # Overwrite files that already exist
-p, [--pretend], [--no-pretend] # Run but do not make any changes
-q, [--quiet], [--no-quiet] # Suppress status output
-s, [--skip], [--no-skip] # Skip files that already exist

Description:
Stubs out a new database migration. Pass the migration name, either
CamelCased or under_scored, and an optional list of attribute pairs as arguments.

A migration class is generated in db/migrate prefixed by a timestamp of the current date and time.

You can name your migration in either of these formats to generate add/remove
column lines from supplied attributes: AddColumnsToTable or RemoveColumnsFromTable

Example:
rails generate migration AddSslFlag

If the current date is May 14, 2008 and the current time 09:09:12, this creates the AddSslFlag migration
db/migrate/20080514090912_add_ssl_flag.rb

`rails generate migration AddTitleBodyToPost title:string body:text published:boolean`

This will create the AddTitleBodyToPost in db/migrate/20080514090912_add_title_body_to_post.rb with this in the Change migration:

  add_column :posts, :title, :string
  add_column :posts, :body, :text
  add_column :posts, :published, :boolean

Migration names containing JoinTable will generate join tables for use with
has_and_belongs_to_many associations.

Example:
rails g migration CreateMediaJoinTable artists musics:uniq

will create the migration

create_join_table :artists, :musics do |t|
  # t.index [:artist_id, :music_id]
  t.index [:music_id, :artist_id], unique: true
end

どなたか、ご教授お願いします！