Code optimization

lib/storages/fsKeysStorage.js

@@ -9,7 +9,7 @@ module.exports = (pathToFile) => {
 		write(data) {
 			return new Promise((resolve, reject) => {
 				fs.writeFile(path, data, { encoding: 'utf8' }, (error) => {
-					if (error) throw error;
+					if (error) reject(error);
 
 					return resolve();
 				});