add root return

cmd/server/main.go

@@ -28,6 +28,16 @@ func main() {
 		DisableStartupMessage: true,
 	})
 
+	app.Get("/", func(c *fiber.Ctx) error {
+		return c.JSON(fiber.Map{
+			"service": "geoip-rest",
+			"endpoints": []string{
+				"/health",
+				"/lookup?ip=<IPv4|IPv6>",
+			},
+		})
+	})
+
 	app.Get("/health", func(c *fiber.Ctx) error {
 		return c.JSON(fiber.Map{"status": "ok"})
 	})