Edit global README.md

[eyalroth]

• describe:

  • what every env variable does
  • project structure
  • CSS structure
  • components and templates?
  • plugins (including local ones and forks)

• integrations:

  • google analytics
  • headless cms
  • utteranc.es/

• warn: first gatsby / node / js project

• developed on: my env (+ gatsby 2)

• link to website

• link to original starter project

• links structure

• tested mostly on:

  1. Windows 10 Chrome (+ Lighthouse audits).
  2. Android phone (Galaxy S7) Chrome.
  3. Android tablet (Samsung Tab S3) Chrome.

• partial testing on:

  1. Windows 10 Edge.
  2. Windows 10 Firefox.

• no tests on apple products (mac / ipad / iphone)

• doesn't support IE