dev: add volumes to dockerfile

dev/Dockerfile.archlinux

@@ -12,4 +12,5 @@ COPY id_ed25519.pub /root/.ssh/authorized_keys
 
 WORKDIR /root/
 COPY entrypoint.sh /
+VOLUME ["/root/.dotfiles"]
 CMD ["bash", "/entrypoint.sh"]

dev/Dockerfile.debian

@@ -13,4 +13,5 @@ COPY id_ed25519.pub /root/.ssh/authorized_keys
 
 WORKDIR /root/
 COPY entrypoint.sh /
+VOLUME ["/root/.dotfiles"]
 CMD ["bash", "/entrypoint.sh"]

dev/README.md

@@ -25,3 +25,32 @@ ansible-playbook -v -i ./ansible-hosts playbooks/setup.yml
 ```
 
 note: the ip address in `ansible-hosts` might have changed from `172.18.0.2`.
+
+## Docker images
+
+- Build: `make build-arch` or `make build-debian` to build the image.
+- Run: `make run` to run the docker container. This bind-mounts `../` to
+  `/root/.dotfiles`, making it possible to test the repo in the container.
+
+## Docker + Ansible
+
+Run `dotfiles-dev` image using `make run`. This starts the container with
+the local repository bind-mounted on `/root/.dotfiles`. To use a custom volume:
+
+```bash
+docker run -v <volume>:/root/dofiles`
+```
+
+Ansible can now be used to test the installation.
+
+```bash
+# this will install dotfiles on the docker container
+ANSIBLE_HOST_KEY_CHECKING=False ansible-playbook -i ansible-hosts \
+				-e local_development=true \
+				../ansible/playbooks/setup.yml
+```
+
+**IMPORTANT** if bind-mounting an already existing repository, run
+`ansible` with `-e local_development=true` to avoid
+clobbering the git history if you have unpushed commit (it won't
+work if your repo is dirty).