code: func (c *Client) DeleteResourceApp(providerID, resourceID, appID string) (*ct.Resource, error) {
  	var resource *ct.Resource
  	return resource, c.Delete(fmt.Sprintf("/providers/%s/resources/%s/apps/%s", providerID, resourceID, appID), &resource)
  }
docs: // DeleteResourceApp removes appID from the resource identified by resourceID and returns the resource