chore: add CODEOWNERS and README for repository setup (#16)

Establish code ownership with core and operations teams, and
provide project documentation for contributors.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: elct9620

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @rubytaiwan/core @rubytaiwan/operations

README.md

@@ -0,0 +1,94 @@
+# Ruby Taiwan
+
+The official website of the [Ruby Taiwan](https://ruby.tw) community, built with [Jekyll](https://jekyllrb.com/) static site generator. The site serves as a central hub for Taiwan's Ruby community, featuring events, blog posts, community campaigns, and related resources.
+
+## Getting Started
+
+### Prerequisites
+
+- Ruby (see `.ruby-version`)
+- Bundler
+
+### Installation
+
+```bash
+bundle install
+```
+
+### Development
+
+```bash
+bundle exec jekyll serve    # Start dev server at http://localhost:4000
+bundle exec jekyll build    # Build static site to _site/
+```
+
+### Linting
+
+```bash
+bundle exec rubocop         # Ruby code style check
+```
+
+## Project Structure
+
+```
+├── _data/          # YAML data files (campaigns, communities, i18n, social media)
+├── _events/        # Event collection (Markdown with front matter)
+├── _includes/      # Reusable Liquid template partials
+├── _layouts/       # Page templates (default, landing, post)
+├── _posts/         # Blog posts (date-based naming convention)
+├── _sass/          # SASS stylesheets (indented .sass syntax)
+│   ├── base/       # Mixins and style guide
+│   └── style/      # Per-section styles
+└── assets/         # Static assets (CSS, JS, images)
+```
+
+## Tech Stack
+
+- **Static Site Generator**: Jekyll
+- **CSS Framework**: Bootstrap 3.4.1
+- **JavaScript**: jQuery 3.7.1 (with Easing and TouchSwipe plugins)
+- **Icons**: Font Awesome 4.7.0
+- **Fonts**: Google Fonts (Montserrat, Lobster)
+- **Stylesheets**: SASS (indented syntax)
+- **Deployment**: GitHub Pages via GitHub Actions
+
+## Contributing
+
+### Adding Events
+
+Create a new file `YYYY-MM-DD-slug.md` in `_events/` with the following front matter:
+
+```yaml
+---
+title: "Event Title"
+date: YYYY-MM-DD
+location: "Venue Name"
+time: "HH:MM"
+event_url: "https://..."
+---
+```
+
+Mark ended events by adding `ended: true` to the front matter.
+
+### Adding Blog Posts
+
+Create a new file `YYYY-MM-DD-slug.md` in `_posts/` with the following front matter:
+
+```yaml
+---
+title: "Post Title"
+cover: "optional-cover-image-url"
+---
+```
+
+### Adding Community Campaigns
+
+Edit `_data/campaigns.yml` to add new campaign entries.
+
+### Translations
+
+UI strings are managed in `_data/i18n.yml`.
+
+## License
+
+This project is maintained by the Ruby Taiwan community.