title: elasticsearch prefix query for multiple words to solve the autocomplete use case
body: <p>How do I get elastic search to work to solve a simple autocomplete use case that has multiple words?</p>
  
  <p>Lets say I have a document with the following title - Elastic search is a great search tool built on top of lucene. </p>
  
  <p>So if I use the prefix query and construct it with the form - </p>
  
  <pre><code>{
      "prefix" : { "title" : "Elas" }
  }
  </code></pre>
  
  <p>It will return that document in the result set. </p>
  
  <p>However if I do a prefix search for </p>
  
  <pre><code>{
      "prefix" : { "title" : "Elastic sea" }
  }
  </code></pre>
  
  <p>I get no results. </p>
  
  <p>What sort of query do I need to construct so as to present to the user that result for a simple autocomplete use case. </p>