Added a Gemspec and a Rake task to build the gem

Rakefile

@@ -1,6 +1,8 @@
+require 'rubygems'
 require 'rake'
 require 'rake/testtask'
 require 'rake/rdoctask'
+require 'rake/gempackagetask'
 
 desc 'Default: run unit tests.'
 task :default => :test
@@ -20,3 +22,31 @@ Rake::RDocTask.new(:rdoc) do |rdoc|
   rdoc.rdoc_files.include('README')
   rdoc.rdoc_files.include('lib/**/*.rb')
 end
+
+spec = Gem::Specification.new do |s|
+  s.name        = %q{factory_girl}
+  s.version     = "1.0"
+  s.summary     = %q{factory_girl provides a framework and DSL for defining and
+                     using model instance factories.}
+  s.description = %q{factory_girl provides a framework and DSL for defining and
+                     using factories - less error-prone, more explicit, and 
+                     all-around easier to work with than fixtures.}
+
+  s.files        = FileList['[A-Z]*', 'lib/**/*.rb', 'test/**/*.rb']
+  s.require_path = 'lib'
+  s.test_files   = Dir[*['test/**/*_test.rb']]
+
+  s.has_rdoc         = true
+  s.extra_rdoc_files = ["README"]
+
+  s.authors = ["Joe Ferris"]
+  s.email   = %q{jferris@thoughtbot.com}
+
+  s.platform = Gem::Platform::RUBY
+  s.add_dependency(%q<activesupport>, [">= 1.0"])
+end
+
+Rake::GemPackageTask.new spec do |pkg|
+  pkg.need_tar = true
+  pkg.need_zip = true
+end