title: Elasticsearch-rails, highlights query
body: <p>I'm trying to get highlights from the Elasticsearch-rails gem, but I can't get it to work.</p>
  
  <p>My search method:</p>
  
  <pre><code>query = {
    query: {
      filtered: {
        query: {
          match: {
            _all: params[:q]
          }
        },
        filter: {
          term: {
            active: true
          }
        }
      },
    },
    highlight: {
      fields: {
        _all: {fragment_size: 150, number_of_fragments: 3}
      }
    }
  }
  
  @results = Elasticsearch::Model.search(query, [Market, Component]).results
  </code></pre>
  
  <p>When I map my results in the view to check if there are any highlights, I get an array of <code>false</code>:</p>
  
  <pre><code>= @results.map(&amp;:highlight?)
  </code></pre>
  
  <p>I read through the Elasticsearch docs here: <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-highlighting.html" rel="nofollow">https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-highlighting.html</a> and the gem's documentation here: <a href="https://github.com/elastic/elasticsearch-rails/tree/master/elasticsearch-model" rel="nofollow">https://github.com/elastic/elasticsearch-rails/tree/master/elasticsearch-model</a> and my query seems to be correct. Not sure how to proceed.</p>