docker: add Dockerfile with instructions

Dockerfile

@@ -0,0 +1,22 @@
+FROM python:3.7-slim
+
+ARG UID
+ARG GID
+
+ENV DEBIAN_FRONTEND noninteractive
+
+ADD edmond /app/edmond
+WORKDIR /app
+
+RUN pip install requests irc
+RUN pip install -r edmond/plugins/requirements.txt
+
+RUN groupadd --gid ${GID} edmond
+RUN useradd --uid ${UID} --gid edmond \
+    --shell /usr/sbin/nologin --create-home --no-log-init \
+    edmond
+
+ENV DEBIAN_FRONTEND teletype
+
+USER edmond
+ENTRYPOINT ["python", "-m", "edmond"]

README.md

@@ -8,14 +8,27 @@ New version of the infamous IRC bot.
 Installation
 ------------
 
-Clone the repository and install main dependencies using Pipenv:
+Clone the repository.
+
+The preferred installation way is using Docker:
 
 ```bash
-pipenv install
+# Build image with dependencies.
+docker build -t edmond --build-arg UID=1000 --build-arg GID=1000 .
+# Run container with config/resources/storage mount.
+docker run -d \
+    -it \
+    -v $(pwd)/config.json:/app/config.json \
+    -v $(pwd)/resources:/app/resources \
+    -v $(pwd)/storage.json:/app/storage.json \
+    edmond \
+    -c config.json
 ```
 
-Plugins dependencies can be manually installed with
+Else you can install dependencies and run it in a virtual env:
 
 ```bash
+pipenv install
 pipenv run pip install -r edmond/plugins/requirements.txt
+pipenv run python -m edmond
 ```