title: Swagger: skipping unknown type "dateTime"
body: <p>I am getting below warning/error while specifying the data type for date and time in swagger spec for loopback. Below is my loopback <code>user.json</code> file</p>
  
  <pre><code>"properties": {
      "schedule": {
        "type": "dateTime",
        "required": true
      },
   }
  </code></pre>
  
  <blockquote>
    <p>Swagger: skipping unknown type "dateTime"</p>
  </blockquote>
  
  <p>Please may I know what is the relevant data type for date and time in swagger?</p>