Ruby on Rails DB Migration Script Using Text instead of :string varchar

I'm a beginner at Ruby on Rails so I apologize if this is quite obvious, but I'm trying to learn how to write the database migration scripts and I'd like to change the following long_description to a text value instead of string:

class CreateArticles < ActiveRecord::Migration
  def self.up  
    create_table :articles do |t|
      t.column "short_description", :string
      t.column "lon开发者_如何学Gog_description", :string
      t.timestamps
    end
  end
end

Any ideas how this is possible?

class CreateArticles < ActiveRecord::Migration
  def self.up
    create_table :articles do |t|
      t.string :short_description
      t.text :long_description
      t.timestamps
    end
  end
  def self.down
    # don't forget the down method
  end
end

Also, don't forget the down method.

Migration types are listed here.

• :string
• :text
• :integer
• :float
• :decimal
• :datetime
• :timestamp
• :time
• :date
• :binary
• :boolean

create_table :articles do |t|
  t.column 'long_description', :text
  # ...
end

Set it to :text

Here's a good ref for you: Here