Server listening on: http://0.0.0.0:9080
GET /ratings/0
(node:1) [MONGODB DRIVER] Warning: Current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.
/opt/microservices/node_modules/mongodb/lib/utils.js:113
      throw err;
      ^

TypeError: Cannot read property 'rating' of undefined
    at /opt/microservices/ratings.js:158:37
    at /opt/microservices/node_modules/mongodb/lib/utils.js:704:5
    at handleCallback (/opt/microservices/node_modules/mongodb/lib/utils.js:109:55)
    at /opt/microservices/node_modules/mongodb/lib/cursor.js:854:66
    at /opt/microservices/node_modules/mongodb/lib/utils.js:704:5
    at /opt/microservices/node_modules/mongodb/lib/cursor.js:939:9
    at Cursor._endSession (/opt/microservices/node_modules/mongodb/lib/core/cursor.js:404:7)
    at /opt/microservices/node_modules/mongodb/lib/cursor.js:937:12
    at maybePromise (/opt/microservices/node_modules/mongodb/lib/utils.js:692:3)
    at Cursor.close (/opt/microservices/node_modules/mongodb/lib/cursor.js:930:12)