added necessary npm packages

node_modules/jsonwebtoken/index.js

@@ -0,0 +1,8 @@
+module.exports = {
+  decode: require('./decode'),
+  verify: require('./verify'),
+  sign: require('./sign'),
+  JsonWebTokenError: require('./lib/JsonWebTokenError'),
+  NotBeforeError: require('./lib/NotBeforeError'),
+  TokenExpiredError: require('./lib/TokenExpiredError'),
+};