code: func (c *Client) IsOrganizationMember(organization, token string) (bool, error) {
  	req, err := c.NewRequest("HEAD", fmt.Sprintf("/user/memberships/orgs/%s", organization), nil)
  	if err != nil {
  		return false, err
  	}
  
  	tokenAuth(req, token)
  
  	resp, err := c.Do(req, nil)
  	if err != nil {
  		if resp != nil && resp.StatusCode == 404 {
  			return false, nil
  		}
  		return false, err
  	}
  
  	return true, nil
  }
docs: // IsOrganizationMember returns true of the authenticated user is a member of the
  // organization.