Updated docs due to error

I was trying to add a new config_template to add an SQS input. I found the following line in the docs and tried to add it to chef_json in the Vagrantfile like so:

``` logstash: {
   instance: {
     server: {
       config_templates: [
         'input_sqs'
       ]
     }
   }
 }```

However I got the following error.

```ERROR: Option templates must be a kind of Hash!  You passed ["input_sqs"]```

In the end I had to do the following: 

``` logstash: {
   instance: {
     server: {
       config_templates: {
         'input_sqs' => 'config/input_sqs.conf.erb'
       }
     }
   }
 }```


This PR updates the docs to show that you need to pass a Hash and not an Array.

I am quite new to Chef, so if this is a mistake on my end I apologise.