make the example data bags actual data bag format and the hierarchy expected by the recipe

Put the example in the format expected by data bags and the hierarchy expected by the recipe 
1. add "id"
2. add environment and move devices under it 

Recipe has:
    data = Chef::DataBagItem.load('elasticsearch', 'data')[node.chef_environment] rescue {}
    default.elasticsearch[:data][:devices] = data['devices'] || {}

which means the data bag should be:
    "id":"data", 
    "node[chef_environment]" : {
        "devices": {
            etc....