Adding extra credit chapters on AppSync and auth

Upgrading Bootstrap and reorganizing chapters

Fixing encoding issue in new eBook

Updating to new eBook format

Using CDK to configure infrastructure resources

Adding section on error handling, upgrading React Router, and using R…

…eact Context

Updating to v4

Updating to serverless-bundle and on-demand DynamoDB

Adding APIG CORS chapter

Refactoring async/await functions