Tests: added Ruby test with constants.

test/ruby/constants/config.ru

@@ -0,0 +1,15 @@
+app = Proc.new do |env|
+    ['200', {
+        'X-Copyright' => RUBY_COPYRIGHT,
+        'X-Description' => RUBY_DESCRIPTION,
+        'X-Engine' => RUBY_ENGINE,
+        'X-Engine-Version' => RUBY_ENGINE_VERSION,
+        'X-Patchlevel' => RUBY_PATCHLEVEL.to_s,
+        'X-Platform' => RUBY_PLATFORM,
+        'X-Release-Date' => RUBY_RELEASE_DATE,
+        'X-Revision' => RUBY_REVISION.to_s,
+        'X-Version' => RUBY_VERSION,
+    }, []]
+end
+
+run app