Finalizing the test strategy and add basic test setup for the API and gateway methods

[kannananil]

As we have started with this project as an experimental one so far we did not added any tests. But as multiple people are collaborating on this and working together to improve the application it is high time to add proper testing for the codes we write.

As part of this card we shall decide and add the basic test setup for the API and gateway methods used in this application

• Finalizing testing strategy
• Deciding the test tooling for backend
• Add basic setup
• Update documentation with instructions on how to setup and run the tests