code: func (s *OrganizationsService) List(ctx context.Context, user string, opt *ListOptions) ([]*Organization, *Response, error) {
  	var u string
  	if user != "" {
  		u = fmt.Sprintf("users/%v/orgs", user)
  	} else {
  		u = "user/orgs"
  	}
  	u, err := addOptions(u, opt)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	req, err := s.client.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	var orgs []*Organization
  	resp, err := s.client.Do(ctx, req, &orgs)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return orgs, resp, nil
  }
docs: // List the organizations for a user. Passing the empty string will list
  // organizations for the authenticated user.
  //
  // GitHub API docs: https://developer.github.com/v3/orgs/#list-user-organizations