loosen dependency for rack, so it runs with Rails 3.2

.travis.yml

@@ -13,6 +13,7 @@ rvm:
   - ruby-head
 matrix:
   include:
+    - { rvm: 1.9.3, env: rack=1.4.0  }
     - { rvm: 1.8.7, env: tilt=master }
     - { rvm: 1.9.3, env: rack=master }
     - { rvm: 1.9.3, env: tilt=master }

sinatra.gemspec

@@ -12,7 +12,7 @@ Gem::Specification.new 'sinatra', Sinatra::VERSION do |s|
   s.extra_rdoc_files  = s.files.select { |p| p =~ /^README/ } << 'LICENSE'
   s.rdoc_options      = %w[--line-numbers --inline-source --title Sinatra --main README.rdoc --encoding=UTF-8]
 
-  s.add_dependency 'rack', '~> 1.5', '>= 1.5.2'
+  s.add_dependency 'rack', '~> 1.4'
   s.add_dependency 'tilt', '~> 1.3', '>= 1.3.4'
   s.add_dependency 'rack-protection', '~> 1.4'
 end