Allow the running of Rails/Merb integration specs independently

Rakefile

@@ -105,17 +105,25 @@ end
 
 namespace :spec do
   desc "Run the integration specs"
-  task :integration do
+  task :integration => ["integration:rails", "integration:merb"]
+
+  namespace :integration do
+    desc "Run the Rails integration specs"
+    task :rails do
       Dir.chdir "spec/integration/rails" do
         result = system "rake test:integration"
         raise "Tests failed" unless result
       end
+    end
 
+    desc "Run the Merb integration specs"
+    task :merb do
       Dir.chdir "spec/integration/merb" do
         result = system "rake spec"
         raise "Tests failed" unless result
       end
     end
+  end
 end
 
 task :default => :spec