def post_update
      post_data = @data.dup
      case @session.type
      when :application
        post_data['deviceIds'] = post_data.delete 'deviceId'
      when :device
        post_data.delete 'deviceId'
      end
      post_data.delete 'tags'
      post_data.delete 'lastSeen'

      grok_self_from post 'device/update', post_data
      self
    end
def post_update
      post_data = @data.dup
      case @session.type
      when :application
        post_data['deviceIds'] = post_data.delete 'deviceId'
      when :device
        post_data.delete 'deviceId'
      end
      post_data.delete 'tags'
      post_data.delete 'lastSeen'

      grok_self_from post 'device/update', post_data
      self
    end
POST the device's +@data+ to the API via 'device/update', and return
 the same object with the new +@data+ returned from API call.