title: Elasticsearch: Document not being added to index with custom mapping
body: <p>I am crawling websites using <code>Scrapy</code>. I want to store the data from each crawl directly to <code>Elasticsearch</code>. I was able to find a pipeline written just for this:
  <a href="https://github.com/jayzeng/scrapy-elasticsearch/blob/master/scrapyelasticsearch/scrapyelasticsearch.py" rel="nofollow noreferrer">https://github.com/jayzeng/scrapy-elasticsearch/blob/master/scrapyelasticsearch/scrapyelasticsearch.py</a> 
  <code>Elasticsearch</code> applies custom mapping to fields if not mentioned otherwise. I created an index on my localhost with a custom mapping (code attached below).
  The index is successfully created and the mapping is also applied. Now when I try to store data in that particular index, no document is added to it. However, if I specify an index that has not been created via custom mapping, documents are added to it. </p>
  
  <p>Code for custom mapping:</p>
  
  <pre><code>from elasticsearch import Elasticsearch
  es = Elasticsearch() 
  
  mapping = {
       "mappings": { 
       "properties": { 
          "name": { 
             "type":  "text" 
         }, 
         "last_updated": { 
            "type": "text" 
         }
  }}}
  
  es.indices.create(index='my-index', ignore=400, body=mapping)
  </code></pre>