Fixes basic template elasticsearch dependency

Fixes #984

Author: picandocodigo

elasticsearch-rails/lib/rails/templates/01-basic.rb

@@ -156,7 +156,7 @@
 say_status  "Rubygems", "Adding Elasticsearch libraries into Gemfile...\n", :yellow
 puts        '-'*80, ''; sleep 0.75
 
-gem 'elasticsearch',       git: 'https://github.com/elasticsearch/elasticsearch-ruby.git'
+gem 'elasticsearch'
 gem 'elasticsearch-model', git: 'https://github.com/elasticsearch/elasticsearch-rails.git'
 gem 'elasticsearch-rails', git: 'https://github.com/elasticsearch/elasticsearch-rails.git'