Add support for Elasticsearch

Review Request #8209 — Created June 2, 2016 and submitted — Latest diff uploaded

Information

Review Board
release-3.0.x
2a24611...

Reviewers

The RB admin panel now includes settings for choosing between Whoosh
(the default) and Elasticsearch as search engines.

Set up Review Board to use Elasticsearch and was able to perform
searches after building the index.