title: Update an Elasticsearch mapping by updating an Index Template
body: <p>I am currently using the config templates to store mappings for my indexes in ES and was wondering... If I updated my mapping in a template file, how would I go about propagating that mapping to already indexed documents? Is there currently a way to reindex the entire index or index type??</p>
  
  <p>Any help is much appreciated!</p>
  
  <p>E</p>