feat: get root dir from git command

pkg/util/path.go

@@ -0,0 +1,18 @@
+package util
+
+import (
+	"log"
+	"os/exec"
+	"strings"
+)
+
+func RootDir() string {
+	cmdOut, err := exec.Command("git", "rev-parse", "--show-toplevel").Output()
+	if err != nil {
+		log.Fatalf("exec.Command: %s", err)
+		return ""
+	}
+
+	rootDir := strings.TrimSpace(string(cmdOut))
+	return rootDir
+}