Improving installation instructions on mac.

[himanshuc3]

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Description

Improving installation, particularly on mac.

Expected Behavior

There were just a few hickups I ran into setting up current development environment. I would like to improve upon in readme.md.

Specifications(For bug reports)

• Node version: 11.2
• Python version: 3.6.4
• npm version: 6.4.1
• Other dependencies:
• Operating system: Mac
• Command line used: terminal

P.S. : I also think the current setup is needs to be cut down. I currently run 4 terminal windows for only running development server which is pretty hacky.