Looks for /data/db folder when looking locally

[taragurung]

When trying to run the node application inside knote-js/01/ locally, it is looking for /data/db created else npm run mongodb will not run. Though this is not exactly an issue but may be if could have mentioned about volume too it would have been great.

[lyqht]

Able to replicate issue with the following logs

2022-05-24T23:05:10.387+0800 I CONTROL  [main] Automatically disabling TLS 1.0, to force-enable TLS 1.0 specify --sslDisabledProtocols 'none'
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten] MongoDB starting : pid=47241 port=27017 dbpath=/data/db 64-bit host=Estees-MacBook-Pro.local
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten] db version v3.7.9-154-g51dce76
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten] git version: 51dce76324173089098e8c9fd09e46b98b32adc4
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten] allocator: system
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten] modules: none
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten] build environment:
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten]     distarch: x86_64
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten]     target_arch: x86_64
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten] options: {}
2022-05-24T23:05:10.395+0800 I STORAGE  [initandlisten] exception in initAndListen: NonExistentPath: Data directory /data/db not found., terminating
2022-05-24T23:05:10.395+0800 I CONTROL  [initandlisten] now exiting
2022-05-24T23:05:10.396+0800 I CONTROL  [initandlisten] shutting down with code:100

Added additional instructions so that users can start mongod with a specified db path.