title: Date picker: timezone shift
body: <h3>Problem</h3>
  
  <p>If I select a date in a <code>&lt;DateInput&gt;</code>, the datetime is in the user's timezone (e.g. <em>2017-07-01T00:00:00.000+02:00</em>) but when it's sent to the server, it's transformed to UTC and thus ends up as <em>2017-06-30T22:00:00.000Z</em>, one day behind.</p>
  
  <p>The underlaying back-end is unaware of the user's timezone and cannot shift the dates back so after stripping the time it ends up with wrong date.</p>
  
  <h3>What would solve my problem</h3>
  
  <p>Any of these options would work fine:</p>
  
  <ol>
  <li>The datetime is sent with the user's timezone.</li>
  <li>The datetime is sent as naive (=without timezone).</li>
  <li>The date selected by the user is already treated as UTC.</li>
  <li>A date only (<em>2017-07-01</em>) instead of the ISO datetime is sent.</li>
  </ol>
  
  <h3>What I tried</h3>
  
  <ul>
  <li>I looked at Admin-on-rest's <code>DateInput</code> <a href="https://marmelab.com/admin-on-rest/Inputs.html#dateinput" rel="noreferrer">documentation</a> and haven't found any option to alter the behaviour.</li>
  <li>I looked at the related Material-UI's <a href="http://www.material-ui.com/#/components/date-picker" rel="noreferrer">documentation</a> and the only somewhat relevant option appears to be <code>DateTimeFormat</code> but despite a couple of tries I got nowhere.</li>
  <li>I checked other answers, e.g <a href="https://stackoverflow.com/questions/37789619/material-ui-time-picker-utc">Material UI Time Picker UTC</a> but cannot figure out how to apply the suggested solution.</li>
  </ul>