Use bundle gem tasks and move gemspec from Rakefile the .gemspec

Rakefile

@@ -1,36 +1,8 @@
-require 'rubygems'
+require 'bundler'
+Bundler::GemHelper.install_tasks
+
 require 'rake/rdoctask'
-require 'rake/gempackagetask'
-require 'rubygems/specification'
 require 'rspec/core/rake_task'
-require 'lib/validates_timeliness/version'
-
-GEM_NAME = "validates_timeliness"
-GEM_VERSION = ValidatesTimeliness::VERSION
-
-spec = Gem::Specification.new do |s|
-  s.name = GEM_NAME
-  s.version = GEM_VERSION
-  s.platform = Gem::Platform::RUBY
-  s.summary = %q{Date and time validation plugin for Rails which allows custom formats}
-  s.description = s.summary
-  s.author = "Adam Meehan"
-  s.email = "adam.meehan@gmail.com"
-  s.homepage = "http://github.com/adzap/validates_timeliness"
-  s.require_path = 'lib'
-
-  s.add_runtime_dependency 'timeliness', '~> 0.3.2'
-
-  s.files       = `git ls-files`.split("\n") - %w{ .rspec .gitignore autotest/discover.rb Gemfile Gemfile.lock }
-  s.test_files  = `git ls-files -- {test,spec,features}/*`.split("\n")
-  s.executables = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
-
-  s.has_rdoc = true
-  s.extra_rdoc_files = ["README.rdoc", "CHANGELOG.rdoc", "LICENSE"]
-end
-
-desc 'Default: run specs.'
-task :default => :spec
 
 desc "Run specs"
 RSpec::Core::RakeTask.new(:spec)
@@ -50,18 +22,5 @@ Rake::RDocTask.new(:rdoc) do |rdoc|
   rdoc.rdoc_files.include('lib/**/*.rb')
 end
 
-Rake::GemPackageTask.new(spec) do |pkg|
-  pkg.gem_spec = spec
-end
-
-desc "Install the gem locally"
-task :install => [:package] do
-  sh %{gem install pkg/#{GEM_NAME}-#{GEM_VERSION}}
-end
-
-desc "Create a gemspec file"
-task :make_spec do
-  File.open("#{GEM_NAME}.gemspec", "w") do |file|
-    file.puts spec.to_ruby
-  end
-end
+desc 'Default: run specs.'
+task :default => :spec