func createUser(c *echo.Context) error {
	u := new(user)
	if err := c.Bind(u); err != nil {
		return err
	}
	users[u.ID] = *u
	return c.JSON(http.StatusCreated, u)
}
func updateUser(c *echo.Context) error {
	u := new(user)
	if err := c.Bind(u); err != nil {
		return err
	}
	id, _ := strconv.Atoi(c.Param("id"))
	users[id].Name = u.Name
	return c.JSON(http.StatusOK, users[id])
}
func createUser(c *echo.Context) error {
	u := &user{
		ID: seq,
	}
	if err := c.Bind(u); err != nil {
		return err
	}
	users[u.ID] = u
	seq++
	return c.JSON(http.StatusCreated, u)
}