feat(settings.py, .env, README.md): Collecting data from .env files

Fixes #25 (closed)

Short description of what this resolves:

Earlier the database credentials were edited in settings.py which caused tracking problem with git. Also, its not a good practice to hardcode credentials. I've added functionality to pick them from .env file and added a .env.example file to create your own env file.

Changes proposed in this pull request:

• Added .env.example
• Documentation for creating .env file
• Added .env and virtual environments in gitignore
• Collecting Database credentials from .env

Preview

Checklist

• My branch is up-to-date with the Upstream develop branch.
• The acceptance, integration, unit tests and linter pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)