Added Evaluation Mode (#251)

[mayankbucha]

Hi @Coteh, evaluation mode for the issue #251 is added. I have used EVALUATION_MODE flag, which when set to true adds evaluation mode and removes uploaded image after 5 mins.
I have also converted startDatabaseClient function callbacks to promise, but they are simple promises and still looks like callbacks. Can we improve them?
Please review

[codecov]

Codecov Report

Merging #288 (2453c9a) into development (7e30d29) will decrease coverage by 0.16%.
The diff coverage is 54.83%.

@@               Coverage Diff               @@
##           development     #288      +/-   ##
===============================================
- Coverage        56.00%   55.83%   -0.17%     
===============================================
  Files               15       15              
  Lines             1150     1166      +16     
===============================================
+ Hits               644      651       +7     
- Misses             506      515       +9     

Impacted Files	Coverage Δ
lib/database-ops.js	55.40% <54.83%> (-0.69%)	⬇️

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[Coteh]

Good work! I have left some feedback for you to take a look at.

[mayankbucha]

Hi @Coteh, I have implemented the changes. Please review

[Coteh]

Good work! Got a couple more suggestions.

[Coteh]

I think we're almost done! Just one more thing I noticed that I didn't before, and a couple of very small adjustments in startDatabaseClient.

I think startDatabaseClient is good enough for now. If there's any more indexes or collections that need to be created in the future, then it should probably be cleaned up to be in a chain of promises or something. I think as more things get added, we can get a good idea of how it can be abstracted.

[mayankbucha]

I have updated the changes. I have mistakenly pushed bat file to start mongodb. I have deleted it and and committed the changes. I cannot figure out why the codecov/patch is failing.

Yes, for startDatabaseClient we could refactor it to be more linear when adding new indexes in future.

I am learning a lot about js, node and github by contributing to this project. Hope to continue resolving issues for the project. 😃

[Coteh]

No problem. I think codecov/patch is failing because there aren't any automated tests that cover those particular lines of code. Usually, some automated unit tests or integration tests would need to be written here to cover those cases, but since there hasn't been any tests written for database-ops yet, I'll merge the changes as-is for this particular case. I have already done some manual testing for this feature and plan on doing some more testing before it reaches mater. Adding automated tests for database-ops is something I'd like to get to at some point though, as that is the preferred and the proper approach.

[Coteh]

Just one more quick change I noticed and I think we should be good to go after that.

Thanks so much for the contribution, and glad you are getting some learning out of this! :D

[Coteh]

LGTM! Thanks again for the contribution! :)