try to finish find

user/find.c

@@ -0,0 +1,12 @@
+#include "kernel/fcntl.h"
+#include "kernel/fs.h"
+#include "kernel/stat.h"
+#include "kernel/types.h"
+#include "user/user.h"
+
+int main(int argc, char *argv[]) {
+  if (argc < 3) {
+    printf("Usage: find path pattern\n");
+  }
+  exit(0);
+}