How to do Rails migration involving Paperclip

Question

How do people write their Rails migrations that involve Paperclip? I feel that I might be missing something obvious as I have now written my own migration helpers hacks that mak

Answer 1

There are generators included in the gem for this:

Rails 2:

script/generate paperclip Class attachment1 (attachment2 ...)

Rails 3:

rails generate paperclip Class attachment1 (attachment2 ...) 

e.g.

rails generate paperclip User avatar 

generates:

class AddAttachmentsAvatarToUser < ActiveRecord::Migration
  def self.up
    add_column :users, :avatar_file_name, :string
    add_column :users, :avatar_content_type, :string
    add_column :users, :avatar_file_size, :integer
    add_column :users, :avatar_updated_at, :datetime
  end

  def self.down
    remove_column :users, :avatar_file_name
    remove_column :users, :avatar_content_type
    remove_column :users, :avatar_file_size
    remove_column :users, :avatar_updated_at
  end
end

Also see the helper methods used in the example in the readme

class AddAvatarColumnsToUser < ActiveRecord::Migration
  def self.up
    change_table :users do |t|
      t.has_attached_file :avatar
    end
  end

  def self.down
    drop_attached_file :users, :avatar
  end
end