code: func UpdateUserActiveOrg(c *m.ReqContext) Response {
  	userID := c.ParamsInt64(":id")
  	orgID := c.ParamsInt64(":orgId")
  
  	if !validateUsingOrg(userID, orgID) {
  		return Error(401, "Not a valid organization", nil)
  	}
  
  	cmd := m.SetUsingOrgCommand{UserId: userID, OrgId: orgID}
  
  	if err := bus.Dispatch(&cmd); err != nil {
  		return Error(500, "Failed to change active organization", err)
  	}
  
  	return Success("Active organization changed")
  }
docs: //POST /api/users/:id/using/:orgId