code: func (c *Controller) PingExample(ctx *gin.Context) {
  	ctx.String(http.StatusOK, "pong")
  	return
  }
docs: // PingExample godoc
  // @Summary ping example
  // @Description do ping
  // @Tags example
  // @Accept json
  // @Produce json
  // @Success 200 {string} string "pong"
  // @Failure 400 {string} string "ok"
  // @Failure 404 {string} string "ok"
  // @Failure 500 {string} string "ok"
  // @Router /examples/ping [get]