feat: watch config reloading

internal/howmuch/howmuch.go

@@ -27,6 +27,7 @@ import (
 	"fmt"
 	"net/http"
 
+	"github.com/fsnotify/fsnotify"
 	"github.com/gin-gonic/gin"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
@@ -79,6 +80,12 @@ func run() error {
 
 	settings, _ := json.MarshalIndent(viper.AllSettings(), "", "  ")
 
+	// watching reloading conf
+	viper.OnConfigChange(func(e fsnotify.Event) {
+		fmt.Println("Config file changed:", e.Name)
+	})
+	viper.WatchConfig()
+
 	fmt.Println(string(settings))
 	fmt.Println(viper.GetString("db.username"))