def update!
      @previously_changed = changes
      # extract only new values to build payload
      payload = Hash[changes.map { |key, values| [SYMBOL_TO_STRING[key.to_sym].to_sym, values[1]] }]
      @changed_attributes.clear

      client.put("/cards/#{id}", payload)
    end
def update!
      @previously_changed = changes
      # extract only new values to build payload
      payload = Hash[changes.map { |key, values| [SYMBOL_TO_STRING[key.to_sym].to_sym, values[1]] }]
      @changed_attributes.clear

      client.put("/cards/#{id}", payload)
    end
Update an existing record.

 Warning: this updates all fields using values already in memory. If
 an external resource has updated these fields, you should refresh!
 this object before making your changes, and before updating the record.

 @raise [Trello::Error] if the card could not be updated.

 @return [String] The JSON representation of the updated card returned by
     the Trello API.