added documentation regarding the PostgreSQL usage instructions.

[Aryan-CC]

Purpose

As the application supports both MySQL and PostgreSQL Database options, added instructions for usage of PostgresSQL.

• ...

Does this introduce a breaking change?

[ ] Yes
[X ] No

Pull Request Type

What kind of change does this Pull Request introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ X] Documentation content changes
[ ] Other... Please describe:

How to Test

• Get the code

git clone [repo-address]
cd [repo-name]
git checkout [branch-name]
npm install

• Test the code

What to Check

Verify that the following are valid

• ...