Fix: save and load appGroup and language in main menu

src/game/lib/session_storage_manager.js

@@ -115,6 +115,23 @@ SessionStorageManager.prototype.getWritingID = function() {
 	return sessionStorage.getItem("writingID");
 }
 
+// main menu
+SessionStorageManager.prototype.setAppGroup = function(value) {
+	sessionStorage.setItem("appGroup", value);
+}
+SessionStorageManager.prototype.getAppGroup = function() {
+	return sessionStorage.getItem("appGroup");
+}
+
+SessionStorageManager.prototype.setLanguage = function(value) {
+	sessionStorage.setItem("language", value);
+}
+SessionStorageManager.prototype.getLanguage = function() {
+	return sessionStorage.getItem("language");
+}
+
+
+
 SessionStorageManager.prototype.resetPlayingAppData = function() {
 	this.removeItem("playingAppID");
 	this.removeItem("playingAppName");