add japanese translation file and translate lesson 1.

quiz-app/src/assets/translations/index.js

@@ -4,6 +4,7 @@ import ko from './ko.json';
 import id from './id.json';
 import hi from './hi.json';
 import it from './it.json';
+import ja from './ja.json';
 
 //export const defaultLocale = 'en';
 
@@ -13,6 +14,7 @@ const messages = {
 	id: id[0],
 	hi: hi[0],
 	it: it[0],
+	ja: ja[0],
 };
 
 export default messages;