Update project README.md with setup instructions

[sscchan]

As a new developer, I am able to set up my development environment using instructions from the repo's README.md file. I should did not need any additional help other then obtaining Auth0 client secrets key-value pair from the project manager.

Acceptance Criteria

• A developer using OSX is able to setup his/her development environment using instructions on the readme file.
• A developer using Linux is able to setup his/her development environment using instructions on the readme file.
• A developer using Windows is able to setup his/her development environment using instructions on the readme file.