bug 4499 ,空map 异常崩溃

@@ -21,9 +21,10 @@ type MiniSearchArticlePageLogic struct {
 
 func NewMiniSearchArticlePageLogic(ctx context.Context, svcCtx *svc.ServiceContext) *MiniSearchArticlePageLogic {
 	return &MiniSearchArticlePageLogic{
-		Logger: logx.WithContext(ctx),
-		ctx:    ctx,
-		svcCtx: svcCtx,
+		Logger:    logx.WithContext(ctx),
+		ctx:       ctx,
+		svcCtx:    svcCtx,
+		userCache: make(map[int64]*domain.User),
 	}
 }