Added a task to generate the gemspec file

Rakefile

@@ -3,6 +3,7 @@ require 'rake'
 require 'rake/testtask'
 require 'rake/rdoctask'
 require 'rake/gempackagetask'
+require 'date'
 
 desc 'Default: run unit tests.'
 task :default => :test
@@ -53,3 +54,10 @@ end
 
 desc "Clean files generated by rake tasks"
 task :clobber => [:clobber_rdoc, :clobber_package]
+
+desc "Generate a gemspec file"
+task :gemspec do
+  File.open("#{spec.name}.gemspec", 'w') do |f|
+    f.write spec.to_ruby
+  end
+end