Include a stacktrace from V8

Author: andygeers

lib/react/renderer.rb

@@ -5,7 +5,8 @@ class Renderer
 
     class PrerenderError < RuntimeError
       def initialize(component_name, props, js_message)
-        message = "Encountered error \"#{js_message}\" when prerendering #{component_name} with #{props}"
+        message = ["Encountered error \"#{js_message}\" when prerendering #{component_name} with #{props}",
+                    js_message.backtrace.join("\n")].join("\n")
         super(message)
       end
     end