code: function () {
      // TODO handling when token is already present
      this.rs.setBackend('dropbox');
      if (this.token){
        hookIt(this.rs);
      } else {
        this.rs.authorize({ authURL: AUTH_URL, scope: '', clientId: this.clientId });
      }
    }
docs: Set the backed to 'dropbox' and start the authentication flow in order
  to obtain an API token from Dropbox.