Resolves #487 - Create a hawtio ElasticSearch plugin

hawtio-web/src/main/webapp/app/elasticsearch/doc/help.md

@@ -1,3 +1,10 @@
 ### Elasticsearch
 
-TODO.
+This hawtio plugin allows to connect to a ElasticSearch (http://www.elasticsearch.org/) server running on a machine (e.g : localhost:9200) and can be query to retrieve
+documents from indices. By default the 'index Sample Docs' will populate an indice 'twitter' and create documents of type 'tweet'.
+
+Remarks :
+
+  - Elasticsearch server must be started locally using command './elasticsearch -f'
+  - By default values can be changed in the config.js file
+