Revert "Don't package test files with gem"

These files are needed for shared specs in delayed_job_active_record,
delayed_job_mongoid, etc.

This reverts commit 27ce6b0.

delayed_job.gemspec

@@ -3,12 +3,13 @@ Gem::Specification.new do |spec|
   spec.authors        = ['Brandon Keepers', 'Brian Ryckbost', 'Chris Gaffney', 'David Genord II', 'Erik Michaels-Ober', 'Matt Griffin', 'Steve Richert', 'Tobias Lütke']
   spec.description    = 'Delayed_job (or DJ) encapsulates the common pattern of asynchronously executing longer tasks in the background. It is a direct extraction from Shopify where the job table is responsible for a multitude of core tasks.'
   spec.email          = ['[email protected]']
-  spec.files          = %w[CHANGELOG.md CONTRIBUTING.md LICENSE.md README.md delayed_job.gemspec]
-  spec.files         += Dir['{contrib,lib,recipes}/**/*']
+  spec.files          = %w[CHANGELOG.md CONTRIBUTING.md LICENSE.md README.md Rakefile delayed_job.gemspec]
+  spec.files         += Dir.glob('{contrib,lib,recipes,spec}/**/*')
   spec.homepage       = 'http://github.com/collectiveidea/delayed_job'
   spec.licenses       = ['MIT']
   spec.name           = 'delayed_job'
   spec.require_paths  = ['lib']
   spec.summary        = 'Database-backed asynchronous priority queue system -- Extracted from Shopify'
+  spec.test_files     = Dir.glob('spec/**/*')
   spec.version        = '4.0.5'
 end