Make Defalut Language Settable

Author: 6543

custom/conf/app.example.ini

@@ -1178,6 +1178,7 @@ JWT_SECRET =
 MAX_TOKEN_LENGTH = 32767
 
 [i18n]
+; List of locales shown in language selector. First element is default language.
 LANGS = en-US,zh-CN,zh-HK,zh-TW,de-DE,fr-FR,nl-NL,lv-LV,ru-RU,uk-UA,ja-JP,es-ES,pt-BR,pt-PT,pl-PL,bg-BG,it-IT,fi-FI,tr-TR,cs-CZ,sr-SP,sv-SE,ko-KR
 NAMES = English,简体中文,繁體中文（香港）,繁體中文（台灣）,Deutsch,français,Nederlands,latviešu,русский,Українська,日本語,español,português do Brasil,Português de Portugal,polski,български,italiano,suomi,Türkçe,čeština,српски,svenska,한국어
 

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -813,7 +813,7 @@ NB: You must have `DISABLE_ROUTER_LOG` set to `false` for this option to take ef
 
 ## i18n (`i18n`)
 
-- `LANGS`: **en-US,zh-CN,zh-HK,zh-TW,de-DE,fr-FR,nl-NL,lv-LV,ru-RU,ja-JP,es-ES,pt-BR,pt-PT,pl-PL,bg-BG,it-IT,fi-FI,tr-TR,cs-CZ,sr-SP,sv-SE,ko-KR**: List of locales shown in language selector
+- `LANGS`: **en-US,zh-CN,zh-HK,zh-TW,de-DE,fr-FR,nl-NL,lv-LV,ru-RU,ja-JP,es-ES,pt-BR,pt-PT,pl-PL,bg-BG,it-IT,fi-FI,tr-TR,cs-CZ,sr-SP,sv-SE,ko-KR**: List of locales shown in language selector. First element is default language.
 - `NAMES`: **English,简体中文,繁體中文（香港）,繁體中文（台灣）,Deutsch,français,Nederlands,latviešu,русский,日本語,español,português do Brasil,Português de Portugal,polski,български,italiano,suomi,Türkçe,čeština,српски,svenska,한국어**: Visible names corresponding to the locales
 
 ## U2F (`U2F`)

modules/translation/translation.go

@@ -68,7 +68,8 @@ func InitLocales() {
 			}
 		}
 	}
-	i18n.SetDefaultLang("en-US")
+
+	i18n.SetDefaultLang(setting.Langs[0])
 
 	allLangs = make([]LangType, 0, i18n.Count()-1)
 	langs := i18n.ListLangs()