adding Exercise 4

CodeExamples/Week4/LiveCodingExamples/chainnedPromises.js

CodeExamples/Week4/LiveCodingExamples/first-app/.gitignore

CodeExamples/Week4/LiveCodingExamples/first-app/README.md

CodeExamples/Week4/LiveCodingExamples/first-app/package.json

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...ples/Week4/LiveCodingExamples/first-app/public/index.html

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...s/Week4/LiveCodingExamples/first-app/public/manifest.json

...ples/Week4/LiveCodingExamples/first-app/public/robots.txt

CodeExamples/Week4/LiveCodingExamples/first-app/src/App.css

CodeExamples/Week4/LiveCodingExamples/first-app/src/App.js

...amples/Week4/LiveCodingExamples/first-app/src/App.test.js

...Examples/Week4/LiveCodingExamples/first-app/src/index.css

CodeExamples/Week4/LiveCodingExamples/first-app/src/index.js

CodeExamples/Week4/LiveCodingExamples/first-app/src/logo.svg

...Week4/LiveCodingExamples/first-app/src/reportWebVitals.js

...ples/Week4/LiveCodingExamples/first-app/src/setupTests.js

CodeExamples/Week4/LiveCodingExamples/first-app/yarn.lock

CodeExamples/Week4/LiveCodingExamples/queues.js