Updated readme to describe repo's purpose

Author: codingkriggs

README.md

@@ -1,2 +1,67 @@
 # github-action-react-deployment
-This barebones project exists to demonstrate how to deploy a React app with GitHub Actions
+
+This is based on the following tutorial:
+
+> https://www.linkedin.com/pulse/automate-react-app-deployment-github-actions-elar-saks-/
+
+The tutorial provides a simple GitHub Actions example for deploying a React App to `github.io`. The repository you are viewing now successfully delivers on that.
+
+View the demo result here:
+
+> https://codingkriggs.github.io/github-action-react-deployment/
+
+You should see "`Edit src/App.js and save to reload.`", the recognizable boilerplate html that is found in that very file, `src/App.js`. This is how we know the code is hosted and React is working.
+
+The tutorial is clear and self-explanatory. However I will draw your attention to differences I've added to this version.
+
+---
+
+## Differences
+
+### Creation of a React project
+
+The tutorial left this as an exercise and prerequisite to the tutorial.
+
+First I created a git repo called `github-action-react-deployment` and hosted it on GitHub.
+
+Within that repo's root directory, I issued the following terminal command to create a react project *as a subdirectory*:
+
+* `npx create-react-app react-deployment-example --template minimal`
+
+### Added support for monorepo design
+
+You'll note that, unlike the tutorial, the react project itself is not at the root, but a subdirectory. I've done this to illustrate how to support multiple projects in a single repo, the so-called monorepo design.
+
+In order to achieve this, the following changes were made compared to the tutorial:
+
+* In `.github/workflows/deploy-react-app.yml`, under yaml's `jobs/deploy-react-to-gh-pages`, I added the following lines:
+  
+  ```yaml
+  defaults:
+    run:
+      working-directory: ./react-deployment-example
+  ```
+
+  This does most actions (except `Deploy`) under that working directory.
+  <br/>
+
+* In the `Deploy` step, rather than
+  
+  ```yaml
+  publish_dir: ./build
+  ```
+
+  I included the child directory:
+
+  ```yaml
+  publish_dir: ./react-deployment-example/build
+  ```
+  <br/>
+
+* The tutorials shows a URL that has the pattern `https://<githubuser>.github.io/react-deployment-example`, but the pattern for this monorepo should instead use the repo name, not the node package name, so `https://<githubuser>.github.io/git-action-react-deployment`.
+
+---
+
+## To summarize
+
+With the changes mentioned above, the tutorial is now transformed to support the monorepo design, supporting multiple child directory packages and projects, even those not part of the NodeJS ecosystem.