docs: add instructions

README.md

@@ -1,3 +1,14 @@
-# cports in docker
+# cports-docker
 
-real
+Run [cports](https://github.com/chimera-linux/cports) and build pkgs inside chimera docker image.
+
+## how?
+
+- run `generate_config.sh` to set your repo directory correctly
+- then run:
+
+```bash
+docker compose run --build --rm cports
+```
+
+- your cports repo will be in /cports, just do setup normally after that