added missing link to the elasticsearch.org website

README.textile

@@ -192,7 +192,7 @@ In order to play with Elastic Search distributed nature, simply bring more nodes
 
 h3. Where to go from here?
 
-We have just covered a very small portion of what ElasticSearch is all about. For more information, please refer to: .
+We have just covered a very small portion of what ElasticSearch is all about. For more information, please refer to the "elasticsearch.org":http://www.elasticsearch.org website.
 
 h3. Building from Source