title: wp-api : How can I update user meta?
body: <p>Right now, I can retrieve users like this ( via Angularjs and angular-wp-api ):
  [everything is written in coffee here]</p>
  
  <pre><code>req=
    method: 'GET'
    url: wpAPIData.base + "/users/me"
    headers:
      'X-WP-Nonce': wpAPIData.nonce
  
  $http(req).success($scope.getData)
  </code></pre>
  
  <p>I can also update simple attrs of any user with this :</p>
  
  <pre><code>req=
    method: 'POST'
    url: wpAPIData.base + "/users/1"
    headers:
      'X-WP-Nonce': wpAPIData.nonce
    data:
      lastname: 'new name'
  $http(req).success($scope.checkData)
  </code></pre>
  
  <p>The problem is, I don't find any way to update user meta within the wp api docs:
  <a href="http://wp-api.org/" rel="nofollow">http://wp-api.org/</a></p>