code: func (o *InvitationManager) Save(invite *JoinOrganizationInvitation) error {
  
  	_, err := o.collection.Upsert(
  		bson.M{
  			"user":         invite.User,
  			"organization": invite.Organization,
  			"role":         invite.Role,
  			"emailaddress": invite.EmailAddress,
  			"phonenumber":  invite.PhoneNumber,
  		}, invite)
  
  	return err
  }
docs: // Save saves/updates an invitation