Update documentation to make it clear which version of ES and ES-php …

…to use

composer.json

@@ -3,7 +3,7 @@
     "description": "Support elasticsearch in Tripal",
     "type": "drupal-module",
     "require-dev": {
-        "elasticsearch/elasticsearch": "^5.2",
+        "elasticsearch/elasticsearch": "~6.0",
         "composer/installers": "~1.0",
         "phpunit/phpunit": "~7.0",
         "statonlab/tripal-test-suite": "~1.1.2"

docker-compose.yml

@@ -9,6 +9,6 @@ services:
       - .:/modules/tripal_elasticsearch
       - ./vendor:/var/www/html/sites/all/libraries/elasticsearch-php
   elasticsearch:
-    image: 'elasticsearch:5'
+    image: 'elasticsearch:6.5.4'
     ports:
-      - "9201:9200"
+      - "9200:9200"

docs/installation.md

@@ -12,7 +12,10 @@ This module can be installed using one of the following methods.
 ```shell
 cd sites/all/modules
 git clone https://github.com/tripal/tripal_elasticsearch.git
-git checkout 7.x-2.0
+
+# OPTIONAL STEP
+git checkout [LATEST VERSION such as 7.x-2.1]
+
 drush en tripal_elasticsearch -y && drush updatedb
 ```
 

docs/prerequisites.md

@@ -17,9 +17,12 @@ If you prefer using a package manager such as `apt` (`apt-get`) or `yum`, you ca
 
 ```
 curl -s http://getcomposer.org/installer | php
-php composer.phar require "elasticsearch/elasticsearch:~5.0"
+php composer.phar require "elasticsearch/elasticsearch"
 ```
 
+If you are using ElasticSearch 6, please make sure composer installs the corresponding elasticsearch:~6.0. Similarly,
+if you are using ElasticSearch 5, make sure to tell composer to install `~5.0`.
+
 For more details, visit the [Elasticsearch PHP library API](https://www.elastic.co/guide/en/elasticsearch/client/php-api/current/_quickstart.html).