fix attachment ENABLED (#4064)

* fix attachment ENABLED

* change wrong name on app.ini.sample

modules/setting/setting.go

@@ -947,7 +947,7 @@ func NewContext() {
 	AttachmentAllowedTypes = strings.Replace(sec.Key("ALLOWED_TYPES").MustString("image/jpeg,image/png,application/zip,application/gzip"), "|", ",", -1)
 	AttachmentMaxSize = sec.Key("MAX_SIZE").MustInt64(4)
 	AttachmentMaxFiles = sec.Key("MAX_FILES").MustInt(5)
-	AttachmentEnabled = sec.Key("ENABLE").MustBool(true)
+	AttachmentEnabled = sec.Key("ENABLED").MustBool(true)
 
 	TimeFormatKey := Cfg.Section("time").Key("FORMAT").MustString("RFC1123")
 	TimeFormat = map[string]string{