Added a generator generator.

railties/lib/generators/rails/generator/USAGE

@@ -0,0 +1,11 @@
+Description:
+    Stubs out a new generator at lib/generators. Pass the generator name, either
+    CamelCased or under_scored, as an argument. 
+
+Example:
+    `./script/generate generator Awesome`
+
+    creates a standard awesome generator:
+        lib/generators/awesome/
+        lib/generators/awesome/awesome_generator.rb
+        lib/generators/awesome/templates/

railties/lib/generators/rails/generator/generator_generator.rb

@@ -0,0 +1,26 @@
+module Rails
+  module Generators
+    class GeneratorGenerator < NamedBase
+      check_class_collision :suffix => "Generator"
+
+      def copy_generator_file
+        template "generator.rb", generator_dir("#{file_name}_generator.rb")
+      end
+
+      def copy_usage_file
+        template "USAGE", generator_dir("USAGE")
+      end
+
+      def create_templates_dir
+        empty_directory generator_dir("templates")
+      end
+
+      protected
+
+        def generator_dir(join)
+          File.join("lib", "generators", file_name, join)
+        end
+
+    end
+  end
+end

railties/lib/generators/rails/generator/templates/USAGE

@@ -0,0 +1,8 @@
+Description:
+    Explain the generator
+
+Example:
+    ./script/generate <%= file_name %> Thing
+
+    This will create:
+        what/will/it/create

railties/lib/generators/rails/generator/templates/generator.rb

@@ -0,0 +1,5 @@
+class <%= class_name %>Generator < Rails::Generators::NamedBase
+  def self.source_root
+    @source_root ||= File.expand_path(File.join(File.dirname(__FILE__), 'templates'))
+  end
+end

railties/test/generators/generator_generator_test.rb

@@ -0,0 +1,26 @@
+require 'abstract_unit'
+require 'generators/generators_test_helper'
+require 'generators/rails/generator/generator_generator'
+
+class GeneratorGeneratorTest < GeneratorsTestCase
+
+  def test_generator_skeleton_is_created
+    run_generator
+
+    %w(
+      lib/generators/awesome
+      lib/generators/awesome/USAGE
+      lib/generators/awesome/templates
+    ).each{ |path| assert_file path }
+
+    assert_file "lib/generators/awesome/awesome_generator.rb",
+                /class AwesomeGenerator < Rails::Generators::NamedBase/
+  end
+
+  protected
+
+    def run_generator(args=["awesome"], config={})
+      silence(:stdout) { Rails::Generators::GeneratorGenerator.start args, config.merge(:root => destination_root) }
+    end
+
+end