ElasticSearch instance fails at loading (wrong)

ElasticSearch (ES from now onwards) will fail to initialize since the parameters for its environment are not correct or absent. These are:

* `cluster.name`: Name of the cluster itself
* `bootstrap.memory_lock`: Needed for ES to [lock the JVM into swap instead of memory](https://www.elastic.co/guide/en/elasticsearch/reference/master/_memory_lock_check.html).
* `"ES_JAVA_OPTS=-Xms256m -Xmx256m"`: [Initial and maximum HEAP size for JVM](https://www.elastic.co/guide/en/elasticsearch/reference/current/_heap_size_check.html). Since it's locked to disk, should be the same. Half the defaults (512m) for development.
* `ulimits: memlock: soft (-1), hard (-1)`: [ES needs to have unlimited access to memory](https://www.elastic.co/guide/en/elasticsearch/reference/current/max-size-virtual-memory-check.html), otherwise it will feel sluggish.  
* `mem_limit: 512m`: Hard limit the memory available for the container.

This can, and should, be changed using `.env` file variables, but it seems that this should suffice for basic ES development.

docker-compose.yml

@@ -473,6 +473,15 @@ services:
       volumes:
         - elasticsearch-data:/usr/share/elasticsearch/data
         - elasticsearch-plugins:/usr/share/elasticsearch/plugins
+      environment:
+        - cluster.name=laradock-cluster
+        - bootstrap.memory_lock=true
+        - "ES_JAVA_OPTS=-Xms256m -Xmx256m"
+      ulimits:
+        memlock:
+          soft: -1
+          hard: -1
+      mem_limit: 512m
       ports:
         - "${ELASTICSEARCH_HOST_HTTP_PORT}:9200"
         - "${ELASTICSEARCH_HOST_TRANSPORT_PORT}:9300"