gin.HandlerFunc
func cors() gin.HandlerFunc {
    return func(c *gin.Context) {
        method := c.Request.Method

        c.Header("Access-Control-Allow-Origin", "*")
        c.Header("Access-Control-Allow-Headers", "Content-Type,AccessToken,X-CSRF-Token, Authorization, Token")
        c.Header("Access-Control-Allow-Methods", "POST, GET, OPTIONS")
        c.Header("Access-Control-Expose-Headers", "Content-Length, Access-Control-Allow-Origin, Access-Control-Allow-Headers, Content-Type")
        c.Header("Access-Control-Allow-Credentials", "true")
        if method == "OPTIONS" {
            c.AbortWithStatus(http.StatusNoContent)
        }
        c.Next()
    }
}
*gin.Engine
engine.Use(cors())