Added Simplified Chinese language pack (#47)

* Added Simplified Chinese language pack

* [i18n] completing ch lang

---------

Co-authored-by: jiulingyun <server@jiulingyun.cn>

frontend/src/locales/index.ts

@@ -1,6 +1,7 @@
 import { createI18n } from 'vue-i18n'
 import en from './en'
 import fa from './fa'
+import ch from './ch'
 
 
 export const i18n = createI18n({
@@ -10,10 +11,12 @@ export const i18n = createI18n({
   messages: {
     en,
     fa,
+    ch
   },
 })
 
 export const languages = [
   { title: 'English', value: 'en' },
+  { title: '简体中文', value: 'ch' },
   { title: 'فارسی', value: 'fa' },
 ]