Pin to elasticsearch API 2.0 for now

Gemfile

@@ -71,6 +71,11 @@ gem 'omniauth-facebook'
 # client for Elasticsearch. Elasticsearch is a flexible
 # and powerful, distributed, real-time search and analytics engine.
 # An example of the use in the project is fuzzy crop search.
+
+# Project does not use semver, so we want to be in sync with the version of 
+# elasticsearch we use
+# See https://github.com/elastic/elasticsearch-ruby#compatibility
+gem "elasticsearch-api", "~> 2.0.0"
 gem "elasticsearch-model"
 gem "elasticsearch-rails"
 

Gemfile.lock

@@ -518,6 +518,7 @@ DEPENDENCIES
   dalli
   database_cleaner (~> 1.5.0)
   devise (>= 4.0.0)
+  elasticsearch-api (~> 2.0.0)
   elasticsearch-model
   elasticsearch-rails
   factory_girl_rails