Add README outlining the posts application

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -0,0 +1,73 @@
+# posts
+
+A small Go application that serves a Markdown blog at <https://posts.monoaf.com>.
+
+Each Markdown file in `content/` is one blog post. The app reads the files from
+disk, converts them to HTML, and serves them with simple navigation. Adding or
+editing a post does not require restarting the app.
+
+## Writing a post
+
+Create `content/YYYY-MM-DD-slug.md`. Front matter is optional:
+
+```markdown
+---
+title: My first post
+date: 2026-10-24
+summary: One line shown on the index page.
+draft: false
+---
+
+Post body in Markdown...
+```
+
+- **title** — falls back to the first `# heading`, then the slug.
+- **date** — falls back to the date in the filename.
+- **summary** — shown on the index page.
+- **draft: true** — hides the post everywhere.
+
+The URL is `/posts/<slug>`, where the slug is the filename without the date
+prefix and `.md` extension.
+
+Posts go through the normal branch-and-PR flow; never push to `main`.
+
+## Pages
+
+| Route | Page |
+|---|---|
+| `/` | All posts, newest first |
+| `/posts/<slug>` | One post, with previous/next links |
+| `/feed.xml` | RSS feed |
+| anything else | 404 page |
+
+Markdown is rendered with [goldmark](https://github.com/yuin/goldmark)
+(CommonMark plus GitHub-style tables, strikethrough and autolinks). Raw HTML in
+posts is not rendered.
+
+## Configuration
+
+Environment variables (on the server, in `/etc/goapps/posts.env`):
+
+| Variable | Default | Meaning |
+|---|---|---|
+| `PORT` | (required) | Port to listen on, bound to `127.0.0.1` |
+| `CONTENT_DIR` | `content` | Directory holding the `.md` posts |
+| `SITE_URL` | `https://posts.monoaf.com` | Absolute base URL used in the RSS feed |
+
+## Development
+
+```sh
+go test ./...
+PORT=8080 go run .
+```
+
+## Deployment
+
+Runs as systemd unit `goapp@posts` on port 8002 behind nginx. Deploy with:
+
+```sh
+deploy-go posts --content
+```
+
+which builds and installs the binary and syncs `content/` to
+`/opt/apps/posts/content/`.