Update Gemfile.

* Use gemspec to retrieve timeliness and other gem specifications.
* Remove test group (since it is the only option) and break groups into AR and Mongoid.

Gemfile

@@ -1,16 +1,20 @@
 source 'http://rubygems.org'
 
-gem 'timeliness', '~> 0.1.1'
+gemspec
 
-group :test do
-  gem 'ZenTest'
-  gem 'rails', '3.0.0'
-  gem 'sqlite3-ruby', :require => 'sqlite3'
+gem 'ZenTest'
+gem 'rails', '3.0.0'
+gem 'rspec', '>= 2.0.0.beta.17'
+gem 'rspec-rails', '>= 2.0.0.beta.17'
+gem 'timecop'
+gem 'rspec_tag_matchers'
+gem 'ruby-debug'
+
+group :mongoid do
   gem 'mongoid', '2.0.0.beta.17'
   gem 'bson_ext', '1.0.4'
-  gem 'rspec', '>= 2.0.0.beta.17'
-  gem 'rspec-rails', '>= 2.0.0.beta.17'
-  gem 'timecop'
-  gem 'rspec_tag_matchers'
-  gem 'ruby-debug'
 end
+
+group :active_record do
+  gem 'sqlite3-ruby', :require => 'sqlite3'
+end

Gemfile.lock

@@ -1,3 +1,9 @@
+PATH
+  remote: .
+  specs:
+    validates_timeliness (3.0.0)
+      timeliness (~> 0.1.0)
+
 GEM
   remote: http://rubygems.org/
   specs:
@@ -117,4 +123,5 @@ DEPENDENCIES
   ruby-debug
   sqlite3-ruby
   timecop
-  timeliness (~> 0.1.1)
+  timeliness (~> 0.1.0)
+  validates_timeliness!