Bump version

Author: tmlee

time_difference.gemspec

@@ -11,7 +11,7 @@ Gem::Specification.new do |gem|
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.name          = "time_difference"
   gem.require_paths = ["lib"]
-  gem.version       = "0.4.2"
+  gem.version       = "0.5.0"
   gem.license = 'MIT'
 
   gem.add_runtime_dependency('activesupport')