Moved generators to lib/generators which is picked up by rails3

generators/paperclip/USAGE

-Usage:
-
-  script/generate paperclip Class attachment1 (attachment2 ...)
-  
-This will create a migration that will add the proper columns to your class's table.
\ No newline at end of file

generators/paperclip/paperclip_generator.rb

-class PaperclipGenerator < Rails::Generator::NamedBase
-  attr_accessor :attachments, :migration_name
- 
-  def initialize(args, options = {})
-    super
-    @class_name, @attachments = args[0], args[1..-1]
-  end
- 
-  def manifest    
-    file_name = generate_file_name
-    @migration_name = file_name.camelize
-    record do |m|
-      m.migration_template "paperclip_migration.rb.erb",
-                           File.join('db', 'migrate'),
-                           :migration_file_name => file_name
-    end
-  end 
-  
-  private 
-  
-  def generate_file_name
-    names = attachments.map{|a| a.underscore }
-    names = names[0..-2] + ["and", names[-1]] if names.length > 1
-    "add_attachments_#{names.join("_")}_to_#{@class_name.underscore}"
-  end
- 
-end

generators/paperclip/templates/paperclip_migration.rb.erb

-class <%= migration_name %> < ActiveRecord::Migration
-  def self.up
-<% attachments.each do |attachment| -%>
-    add_column :<%= class_name.underscore.camelize.tableize %>, :<%= attachment %>_file_name, :string
-    add_column :<%= class_name.underscore.camelize.tableize %>, :<%= attachment %>_content_type, :string
-    add_column :<%= class_name.underscore.camelize.tableize %>, :<%= attachment %>_file_size, :integer
-    add_column :<%= class_name.underscore.camelize.tableize %>, :<%= attachment %>_updated_at, :datetime
-<% end -%>
-  end
-
-  def self.down
-<% attachments.each do |attachment| -%>
-    remove_column :<%= class_name.underscore.camelize.tableize %>, :<%= attachment %>_file_name
-    remove_column :<%= class_name.underscore.camelize.tableize %>, :<%= attachment %>_content_type
-    remove_column :<%= class_name.underscore.camelize.tableize %>, :<%= attachment %>_file_size
-    remove_column :<%= class_name.underscore.camelize.tableize %>, :<%= attachment %>_updated_at
-<% end -%>
-  end
-end

lib/generators/paperclip/USAGE

+Description:
+    Explain the generator
+
+Example:
+    rails generate paperclip Thing
+
+    This will create:
+        what/will/it/create

lib/generators/paperclip/paperclip_generator.rb

+class PaperclipGenerator < Rails::Generators::Base
+  include Rails::Generators::Migration
+
+  desc "Create a migration to add paperclip-specific fields to your model."
+
+  argument :attachment_class, :required => true, :type => :string, :desc => "The class to migrate.",
+           :banner => "ClassName"
+  argument :attachment_names, :required => true, :type => :array, :desc => "The names of the attachment(s) to add.",
+           :banner => "attachment_one attachment_two attachment_three ..."
+
+  def self.source_root
+    @source_root ||= File.expand_path('../templates', __FILE__)
+  end
+
+  def generate_migration
+    migration_template "paperclip_migration.rb.erb", "db/migrate/#{migration_file_name}"
+  end
+
+  protected
+
+  def migration_name
+    "add_attachment_#{attachment_names.join("_")}_to_#{attachment_class.underscore}"
+  end
+
+  def migration_file_name
+    "#{migration_name}.rb"
+  end
+
+  def migration_class_name
+    migration_name.camelize
+  end
+
+  def self.next_migration_number(dirname) #:nodoc:
+    Time.now.strftime("%Y%m%d%H%M%S")
+  end
+
+end

lib/generators/paperclip/templates/paperclip_migration.rb.erb

+class <%= migration_class_name %> < ActiveRecord::Migration
+  def self.up
+<% attachment_names.each do |attachment| -%>
+    add_column :<%= attachment_class.underscore.camelize.tableize %>, :<%= attachment %>_file_name, :string
+    add_column :<%= attachment_class.underscore.camelize.tableize %>, :<%= attachment %>_content_type, :string
+    add_column :<%= attachment_class.underscore.camelize.tableize %>, :<%= attachment %>_file_size, :integer
+    add_column :<%= attachment_class.underscore.camelize.tableize %>, :<%= attachment %>_updated_at, :datetime
+<% end -%>
+  end
+
+  def self.down
+<% attachment_names.each do |attachment| -%>
+    remove_column :<%= attachment_class.underscore.camelize.tableize %>, :<%= attachment %>_file_name
+    remove_column :<%= attachment_class.underscore.camelize.tableize %>, :<%= attachment %>_content_type
+    remove_column :<%= attachment_class.underscore.camelize.tableize %>, :<%= attachment %>_file_size
+    remove_column :<%= attachment_class.underscore.camelize.tableize %>, :<%= attachment %>_updated_at
+<% end -%>
+  end
+end