Unlock Appraisal dependency

Gemfile.lock

@@ -136,7 +136,7 @@ PLATFORMS
 
 DEPENDENCIES
   activerecord-jdbcsqlite3-adapter
-  appraisal (~> 0.4.0)
+  appraisal
   aruba
   aws-sdk
   bourne

paperclip.gemspec

@@ -32,7 +32,7 @@ Gem::Specification.new do |s|
   s.add_dependency('mime-types')
 
   s.add_development_dependency('shoulda')
-  s.add_development_dependency('appraisal', '~> 0.4.0')
+  s.add_development_dependency('appraisal')
   s.add_development_dependency('mocha')
   s.add_development_dependency('aws-sdk')
   s.add_development_dependency('bourne')