Updated README.md file including the steps for setting up Google Auth…

[vishwaikon]

Purpose

Updated README.md file including the steps for setting up Google Authentication, enabling Google+ API for the project, creation of OAuth consent screen, OAuth client ID credentials and setting up environmental variables.

This PR fix #94

Goals

To support contributors setup Google authentication, enabling Google+ API, creation of OAuth consent screen, client ID credentials and setting up environmental variables.

Approach

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Screenshots

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 )
• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation

Related PRs

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Test environment

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Learning

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