Add ntfy config settings

internal/config/repository.go

@@ -1,6 +1,10 @@
 package config
 
-import "gorm.io/gorm"
+import (
+	"errors"
+
+	"gorm.io/gorm"
+)
 
 type Repository struct {
 	db *gorm.DB
@@ -37,3 +41,15 @@ func (r *Repository) List() ([]ConfigEntry, error) {
 	}
 	return entries, nil
 }
+
+func (r *Repository) CreateIfMissing(key, value string) error {
+	var e ConfigEntry
+	err := r.db.First(&e, "key = ?", key).Error
+	if err == nil {
+		return nil
+	}
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		return r.db.Create(&ConfigEntry{Key: key, Value: value}).Error
+	}
+	return err
+}