override title when installed cleanly

lib/models/config.js

@@ -27,6 +27,7 @@ module.exports = function(crowi) {
     let config = getDefaultCrowiConfigs();
 
     // overwrite
+    config['app:title'] = 'crowi-plus';
     config['security:isEnabledPassport'] = true;
     config['customize:behavior'] = 'crowi-plus';
     config['customize:layout'] = 'crowi-plus';