title: Elastic search exact range for date
body: <p>Trying to do 'exact' date match using range query but without success.
  I have <code>agreement_start_date</code> field with below mapping </p>
  
  <pre><code>"agreement_start_date" : {
       "type" : "date",
       "format" : "strict_date_optional_time||epoch_millis"
  } 
  </code></pre>
  
  <p>I have indexed single document and it seems to be indexed fine. </p>
  
  <pre><code>curl "localhost:9200/cr/_search?pretty=true" -d ''
  
  {
    "took" : 35,
    "timed_out" : false,
    "_shards" : {
      "total" : 5,
      "successful" : 5,
      "failed" : 0
    },
    "hits" : {
      "total" : 1,
      "max_score" : 1.0,
      "hits" : [ {
        "_index" : "cr",
        "_type" : "agreement_index",
        "_id" : "570fe59b7f9e6f7f762129ed",
        "_score" : 1.0,
        "_source":{"agreement_start_date": "2016-04-14T18:46:51.268176+00:00"} 
    }
  }
  </code></pre>
  
  <p>I want to get this record with simple query that match <code>agreement_start_date</code> with particular day.</p>
  
  <pre><code>{
    "query": {
      "bool": {
        "must": {
          "range": {
            "agreement_start_date": {
              "gte": "2016-04-14",
              "lte": "2016-04-14",
              "format": "yyyy-MM-dd"
            }
          }
        }
      }
    }
  }
  </code></pre>
  
  <p>This query return 0 results. How to make query in elastic search which compare only provided parts of date?</p>