async function userSeen(req, res) {
    const user = await gladys.house.userSeen(req.params.house_selector, req.params.user_selector);
    res.json(user);
  }
@api {post} /api/v1/house/:house_selector/user/:user_selector/seen user seen
@apiName userSeen
@apiGroup House
@apiDescription Call this API if a user is seen in a house.
@apiSuccessExample {json} Success-Example
{
  "id": "e4e3f03e-60b9-485e-bc0a-c582b69089bd",
  "firstname": "tony",
  "lastname": "Stark",
  "selector": "tony",
  "email": "tony.stark@gladysassistant.com",
  "current_house_id": "7932e6b3-b944-49a9-8d63-b98b8ecb2509",
  "last_house_changed": "2019-05-09T03:57:53.034Z"
}