Update README.md

Author: pusewicz

README.md

@@ -1,35 +1,79 @@
 mruby.org
 =========
 
-This is the [Jekyll](https://jekyllrb.com/) source of
-the [mruby.org](https://mruby.org/) website.
+This is the [Jekyll](https://jekyllrb.com/) source of the [mruby.org](https://mruby.org/) website.
 
-## Preview
+## Prerequisites
 
-The following will give you a preview of the site.
+- **Ruby** — version is specified in `.ruby-version`
+- **Bundler** — `gem install bundler`
+- **`gh` CLI** — required by `gen:mrbdoc` and `gen:releasedata` to query the GitHub API
 
-Install bundler:
+## Local development
 
 ```shell
-gem install bundler
+git clone https://github.com/mruby/mruby.github.io
+cd mruby.github.io
+bundle install
 ```
 
-Clone the repository:
+Serve the site locally with live reload:
 
 ```shell
-git clone https://github.com/mruby/mruby.github.io
+bundle exec rake serve
+# or use the convenience script:
+./server
 ```
 
-Install Jekyll and its dependencies:
+## Build
+
+Runs all data generation tasks then builds the Jekyll site:
 
 ```shell
-cd mruby.github.io
-bundle install
+bundle exec rake build
 ```
 
-Preview the site:
+## Data generation tasks
+
+Each task can also be run individually:
+
+### `rake gen:mgemdata`
+
+Regenerates `_data/mgems.yml` from the mrbgems registry. Do not edit this file manually.
+
+```shell
+bundle exec rake gen:mgemdata
+```
+
+### `rake gen:mrbdoc`
+
+Clones the latest stable mruby release into `mruby/`, generates YARD API documentation, and copies it to `docs/api/`. Requires the `gh` CLI.
 
 ```shell
-bundle exec jekyll serve
-open "http://localhost:4000"
+bundle exec rake gen:mrbdoc
 ```
+
+### `rake gen:contributors`
+
+Generates `_data/contributors.yml` from the mruby `AUTHORS` file. Requires `mruby/` to exist (run `gen:mrbdoc` first). The `CONTRIBUTOR_THRESHOLD` environment variable sets the minimum commit count (default: 10).
+
+```shell
+bundle exec rake gen:contributors
+CONTRIBUTOR_THRESHOLD=20 bundle exec rake gen:contributors
+```
+
+### `rake gen:releasedata`
+
+Generates `_data/releases.yml` from the GitHub API. Requires the `gh` CLI.
+
+```shell
+bundle exec rake gen:releasedata
+```
+
+## Deployment
+
+GitHub Actions (`.github/workflows/pages.yml`) triggers on push to `master`. It runs `bundle exec rake build` (with `GH_TOKEN` set for the `gh` CLI calls) and deploys the result to GitHub Pages via `actions/deploy-pages`.
+
+## CI
+
+The lint workflow (`.github/workflows/lint.yml`) runs on all pull requests and checks for spelling errors (`misspell`) and merge conflict markers.