chore: add README to explain how the templating is set up

.github/workflows/templating.yml

@@ -23,7 +23,7 @@ jobs:
         run: |
           git config user.name 'github-actions[bot]'
           git config user.email 'github-actions[bot]@users.noreply.github.com'
-          rm -rf template index.js .gitignore package-lock.json
+          rm -rf template index.js .gitignore package-lock.json README.md
           cp -rT output .
           rm -rf output
           git add -A

README.md

@@ -0,0 +1,55 @@
+# Toolkit Template
+
+Repository template for creating a new Web Component, specifically
+tailored to be part of the
+[Web at Illinois](https://github.com/web-illinois) Web Implementation
+Guidelines Group (WIGG) [Toolkit](https://github.com/web-illinois/toolkit-management).
+
+## How To Use
+
+> [!IMPORTANT]
+> Follow the [steps in the toolkit-management documentation](https://github.com/web-illinois/toolkit-management/blob/main/documentation/README.md)
+> to contribute a component to the toolkit.
+
+## How this template works
+
+The content that will be in the resulting repository is templated under
+the [`template`](./template) directory. The templating is configured
+in [`index.js`](./index.js), and uses a simple scaffolding tool called
+[CAZ](https://github.com/zce/caz).
+
+There is a [templating GitHub Workflow](./.github/workflows/templating.yml) in this
+repository that's configured to run only once when the template is used.
+That workflow executes CAZ to scaffold the repository to the proper contents
+with the naming determined by the new repository's name.
+
+CAZ accepts input using "prompts", which can be specified in the command
+line invocation of the tool. The workflow specifies the values to those
+prompts, and CAZ takes care of the rest.
+
+Finally, the workflow commits the changes to the new repository. This usually
+takes less than 10 seconds. Once done, the repository is ready to be worked on.
+
+## Developing this template
+
+### Adding files
+
+New files can be added to the [`template`](./template) directory, and they
+are automatically picked up.
+
+- Substitutions in file names happen with curly braces, `{variable}`
+- Inside files, [lodash](https://lodash.com/docs#template) templates are used,
+  which uses `<%= variable %>` as delimiters.
+
+> [!NOTE]
+> GitHub Workflows cannot be templated, and so must be entirely dynamic
+> and contained in the main [`.github/workflows`](./.github/workflows) directory.
+
+### Adding Variables
+
+If additional variables are needed, they must be added in two locations:
+
+1. In [`index.js`](./index.js) as prompts.
+2. In the [workflow](./.github/workflows/templating.yml), they need to be
+   given values as arguments for the `caz` command.
+