Add puppet-lint-alias-check gem

Gemfile

@@ -19,6 +19,7 @@ group :development, :unit_tests do
   gem 'puppet-lint-version_comparison-check',              :require => false
   gem 'puppet-lint-fileserver-check',                      :require => false
   gem 'puppet-lint-file_source_rights-check',              :require => false
+  gem 'puppet-lint-alias-check',                           :require => false
   gem 'rspec-puppet-facts',                                :require => false
 end