Create the `elasticsearch` user as "system" user to avoid UID/GID collisions
Create the `elasticsearch` user as "system" user to avoid UID/GID collisions

Closes #159

vacay/vcy-elasticsearch,michaeld/elasticsearch-cookbook,gilt/cookbook-elasticsearch,zzugg/cookbook-elasticsearch,spuder/cookbook-elasticsearch,spuder/cookbook-elasticsearch,gilt/cookbook-elasticsearch,spuder/cookbook-elasticsearch,nbudin/cookbook-elasticsearch,zzugg/cookbook-elasticsearch,gouketsu/cookbook-elasticsearch,vacay/vcy-elasticsearch,vacay/vcy-elasticsearch,paulczar/cookbook-elasticsearch,zzugg/cookbook-elasticsearch,gilt/cookbook-elasticsearch,gouketsu/cookbook-elasticsearch,gouketsu/cookbook-elasticsearch,nbudin/cookbook-elasticsearch,nbudin/cookbook-elasticsearch,GemHQ/cookbook-elasticsearch