Fix the issue where the backend API URL was not configurable.

Purpose

The purpose of this PR is to fix #69

Goals

This PR makes the backend API URL configurable through the VITE_API_URL environment variable. This allows the application to connect to different backend APIs depending on the environment.

Approach

I updated the README.md file to include instructions on how to set the VITE_API_URL environment variable. See the changes in this PR for more details.

Screenshots

N/A

Checklist

[x] This PR doesn't commit any keys, passwords, tokens, usernames, or other secrets.
[x] I have read and understood the development best practices guidelines ( http://bit.ly/sef-best-practices )
[x] My code follows the style guidelines of this project
[x] I have performed a self-review of my own code
[x] I have commented my code, particularly in hard-to-understand areas
[x] I have made corresponding changes to the documentation

Related PRs

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Test environment

OS - Fedora Linux 39 (KDE Plasma) x86_64 NodeJS - 20.10.0

Learning

I learned about the importance of making backend API URLs configurable to support different environments. I also learned about Vite's support for loading environment variables.

sef-global / scholarx-frontend