Add docker image

Dockerfile

@@ -0,0 +1,21 @@
+FROM alpine:3.4
+
+RUN set -xe \
+    && apk --no-cache add \
+        bash \
+        enchant \
+        aspell-en \
+        git \
+        make \
+        python \
+        py-pip
+
+ADD requirements.txt .
+
+RUN pip install -r requirements.txt --no-cache-dir
+
+WORKDIR /doc
+
+VOLUME ["/doc"]
+
+CMD ["/bin/bash"]

development/documentation.rst

@@ -1,8 +1,51 @@
 Building the Documentation
---------------------------
+==========================
 
-First `install Sphinx`_ and `install enchant`_ (e.g. ``sudo apt-get install enchant``),
-then download the requirements:
+We build the documentation with Sphinx. You could install it on your system or use Docker.
+
+
+Install Sphinx
+--------------
+
+
+Install on local machine
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+The installation for Sphinx differs between system. See `Sphinx installation page`_ for details. When Sphinx is
+installed you need to `install enchant`_ (e.g. ``sudo apt-get install enchant``).
+
+
+Using Docker
+~~~~~~~~~~~~
+
+If you are using docker. Run the following commands from the repository root.
+
+.. code-block:: bash
+
+    $ docker run --rm -it -v "$PWD":/doc phphttp/documentation
+    $ # You are now in the docker image
+    $ make html
+    $ make spelling
+
+Alternatively you can run the commands directly from the host
+without entering the container shell:
+
+.. code-block:: bash
+
+    $ docker run --rm -t -v "$PWD":/doc phphttp/documentation make html
+    $ docker run --rm -t -v "$PWD":/doc phphttp/documentation make spelling
+
+.. warning::
+
+    The Docker container runs with `root` user by default
+    which means the owner of the generated files will be `root`
+    on the host too.
+
+
+Build documentation
+-------------------
+
+Before we can build the documentation we have to make sure to install all requirements.
 
 .. code-block:: bash
 
@@ -15,6 +58,6 @@ To build the docs:
     $ make html
     $ make spelling
 
-.. _install Sphinx: http://sphinx-doc.org/latest/install.html
+.. _Sphinx installation page: http://sphinx-doc.org/latest/install.html
 .. _install enchant: http://www.abisource.com/projects/enchant/