[FEATURE REQUEST] Implement queueing system

[anzharip]

Is your feature request related to a problem? Please describe.
Currently when the service crashed, the incoming tweet and tweet to be sent is lost. The current queue is only a simple in-memory array.

Describe the solution you'd like
I'd like to have a more robust queueing system, so that when the service crashed due to an unexpected exception, the incoming tweet and tweet to be sent will still be intact, and the processing can resume.

Describe alternatives you've considered

• Solutions like AWS SQS (https://aws.amazon.com/sqs/).
• Redis + bull.

Additional context
n/a