Use activesupport gem rather than active_support

Rakefile

@@ -10,7 +10,7 @@ begin
     gem.email = "tcrawley@gmail.com"
     gem.homepage = "http://github.com/tobias/zendesk_remote_auth"
     gem.authors = ["Tobias Crawley"]
-    gem.add_dependency "active_support", ">= 3.0.0"
+    gem.add_dependency "activesupport", ">= 3.0.0"
     gem.add_development_dependency "rspec", ">= 2.6.0"
     # gem is a Gem::Specification... see http://www.rubygems.org/read/chapter/20 for additional settings
   end

zendesk_remote_auth.gemspec

@@ -34,14 +34,14 @@ Gem::Specification.new do |s|
     s.specification_version = 3
 
     if Gem::Version.new(Gem::VERSION) >= Gem::Version.new('1.2.0') then
-      s.add_runtime_dependency(%q<active_support>, [">= 3.0.0"])
+      s.add_runtime_dependency(%q<activesupport>, [">= 3.0.0"])
       s.add_development_dependency(%q<rspec>, [">= 2.6.0"])
     else
-      s.add_dependency(%q<active_support>, [">= 3.0.0"])
+      s.add_dependency(%q<activesupport>, [">= 3.0.0"])
       s.add_dependency(%q<rspec>, [">= 2.6.0"])
     end
   else
-    s.add_dependency(%q<active_support>, [">= 3.0.0"])
+    s.add_dependency(%q<activesupport>, [">= 3.0.0"])
     s.add_dependency(%q<rspec>, [">= 2.6.0"])
   end
 end