add version and generate gem file

to_csv.gemspec

@@ -0,0 +1,21 @@
+# encoding: utf-8
+
+require File.expand_path('../version', __FILE__)
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "to_csv"
+  s.version     = ToCsv::VERSION
+  s.summary     = "Export data to csv on Rails"
+  s.description = "This simple plugin gives you the ability to call to_csv to a collection of activerecords. The builder options are the same as to_json / to_xml, except for the :include."
+
+  s.required_ruby_version     = '>= 1.8.7'
+  s.required_rubygems_version = ">= 1.3.6"
+
+  s.authors     = ["LiangWenKe"]
+  s.email       = ["liangwenke8@gmail.com"]
+  s.homepage    = "http://www.liangwenke.com"
+  s.rubyforge_project = "to_csv"
+
+  s.require_path = 'lib'
+end

version.rb

@@ -0,0 +1,11 @@
+module ToCsv
+  # module VERSION
+  #   MAJOR = 1
+  #   MINOR = 0
+  #   TINY  = 0
+  #   PRE   = "beta"
+  # 
+  #   STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
+  # end
+  VERSION = "1.0.0"
+end