all these changes

backend/node_modules/jsonwebtoken/lib/TokenExpiredError.js

@@ -0,0 +1,13 @@
+var JsonWebTokenError = require('./JsonWebTokenError');
+
+var TokenExpiredError = function (message, expiredAt) {
+  JsonWebTokenError.call(this, message);
+  this.name = 'TokenExpiredError';
+  this.expiredAt = expiredAt;
+};
+
+TokenExpiredError.prototype = Object.create(JsonWebTokenError.prototype);
+
+TokenExpiredError.prototype.constructor = TokenExpiredError;
+
+module.exports = TokenExpiredError;