fix: handle nil setting in user retrieval from database

Author: Calcium-Ion

model/user.go

@@ -1,6 +1,7 @@
 package model
 
 import (
+	"database/sql"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -853,10 +854,17 @@ func GetUserSetting(id int, fromDB bool) (settingMap dto.UserSetting, err error)
 		// Don't return error - fall through to DB
 	}
 	fromDB = true
-	err = DB.Model(&User{}).Where("id = ?", id).Select("setting").Find(&setting).Error
+	// can be nil setting
+	var safeSetting sql.NullString
+	err = DB.Model(&User{}).Where("id = ?", id).Select("setting").Find(&safeSetting).Error
 	if err != nil {
 		return settingMap, err
 	}
+	if safeSetting.Valid {
+		setting = safeSetting.String
+	} else {
+		setting = ""
+	}
 	userBase := &UserBase{
 		Setting: setting,
 	}