code: func (ctx *Context) SetCookie(key string, value string, expire int) {
  	now := time.Now()
  	cookie := &http.Cookie{
  		Name:   key,
  		Value:  value,
  		Path:   "/",
  		MaxAge: expire,
  	}
  	if expire != 0 {
  		expireTime := now.Add(time.Duration(expire) * time.Second)
  		cookie.Expires = expireTime
  	}
  	http.SetCookie(ctx.Response, cookie)
  }
docs: // SetCookie set cookies for the request. If expire is 0, create a session cookie.