Add Docker support

Dockerfile

@@ -0,0 +1,10 @@
+FROM python:3.6-alpine
+WORKDIR /tmp
+
+COPY . .
+RUN adduser -S slappd && \
+    pip install --upgrade . && \
+    rm -rf /tmp/*
+
+USER slappd
+ENTRYPOINT ["/usr/local/bin/slappd"]

README.md

@@ -27,7 +27,17 @@ This script is designed to be run from crontab, and issues one API call per run.
 
 ### Installation & Configuration
 
+If this is your first time, create the default config file with `make config`
+and then edit it (`~/.config/slappd/slappd.cfg`) to reflect your API information
+and friends list.
+
+#### Docker
+
+* Run `make docker-run` to build and run Slappd. **Note:** This mounts the
+  config you created earlier into the container to keep track of which check-ins
+  it has seen.
+
+#### Virtualenv
+
 * Install Slappd to a virtualenv via `make install`.
-* If this is your first time, create the default config file with `make config`
-  and then edit it `(~/.config/slappd/slappd.cfg)` to reflect your API information.
-* Run it from crontab: `*/5 * * * ~/.virtualenv/slappd/bin/slappd > /dev/null 2>&1`
+* Run it from crontab: `*/5 * * * ~/.virtualenv/slappd/bin/slappd > /dev/null 2>&1`

makefile

@@ -13,6 +13,14 @@ dev: ${VIRTUALENV_DIR}/slappd
 		pip install -U flake8 pip && \
 		pip install --editable .
 
+.PHONY: docker-build
+docker-build:
+	docker build -t slappd .
+
+.PHONY: docker-run
+docker-run: docker-build
+	docker run -v ${HOME}/.config/slappd:/home/slappd/.config/slappd slappd
+
 .PHONY: install
 install: ${VIRTUALENV_DIR}/slappd
 	source ${VIRTUALENV_DIR}/slappd/bin/activate && \