Integrating db_middleware and queue_worker

[pranavacharya]

@rishi1596 we need to integrate db_middleware and queue_worker.

Flow of fetching data from S3 and writing to DB is yet to be checked.

[pranavacharya]

I have opened PR #33 for this integration.

I had to some changes to integrate both service. Also, refactored some of your code.

[pranavacharya]

Let's finish #33 then we can proceed to merge #27

[pranavacharya]

#33 is ready to merge

Note : Fix TODO: complete updateStatusOfRequestInDB function before closing #27