Document build & deploy process, cf. ooc-lang/rock#972

Makefile

@@ -1,8 +1,5 @@
 
 .PHONY: deploy
 
-deploy: build
-	s3cmd -P sync --delete-removed output/* s3://ooc-lang.org/
-
 build:
 	bundle exec nanoc

README.md

@@ -1,5 +1,48 @@
-# ooc site
+# ooc-lang.org
 
-This is the source for the [ooc website][ooc].
+This is the Markdown sources for the ooc language website, <https://ooc-lang.org>
 
-[ooc]: http://ooc-lang.org/
+## Building
+
+[nanoc][] is used to transform Markdown into HTML. It's a piece of ruby software.
+
+To build the website, make sure you have Ruby 2.x+, run this once:
+
+```bash
+bundle install
+```
+
+(If you don't have `bundle`, get it with `gem install bundler`)
+
+And then run this everytime you want to build it:
+
+```bash
+bundle exec nanoc
+```
+
+[nanoc]: http://nanoc.ws/
+
+## Deploying
+
+nanoc produces output in the `output/` directory as per `nanoc.yaml`, we host
+the website on Github Pages for free hosting, which means you can deploy by
+doing the following:
+
+Once:
+
+```bash
+git clone git@github.com:ooc-lang/ooc-lang.github.io.git output
+```
+
+After building the site, every time you want to deploy:
+
+```bash
+(cd output && git add . && git commit -m "Changed this and that" && git push origin master)
+```
+
+(Note: since the deploy repo is named `ooc-lang.github.io`, the `master` branch
+is used rather than the `gh-pages` branch.)
+
+## Links
+
+  * The nanoc project: <http://nanoc.ws/>