update docs

docs/rpi_build.rst

@@ -0,0 +1,19 @@
+.. _rpi_build:
+
+Building for a Raspberry Pi
+===========================
+
+The build does not need to be done on the Pi.
+
+To do so, go to ``tests/`` and call ``./build_arm.sh``, it will build all necessary images for arm.
+
+To push the locally built images to a remote server, run ``./deploy_to_pi.sh``. Docker 18.09+ is needed to use ``-H ssh://<user>@<host>``.
+
+Adjustments
+-----------
+
+``build_arm.sh`` uses some variables passed as ``build-arg`` to docker-compose:
+
+- ``DISTRO``: is the main distro used (ie: alpine:3.8)
+- ``PHP_DISTRO``: is used for the ``rainloop`` and ``roundcube`` images
+- ``EDGE_DISTRO``: is used for ``radicale`` as edge has dulwich and radicale as packages

docs/setup.rst

@@ -19,9 +19,7 @@ Prepare the environment
 
 Mailu images are designed to work on x86 or equivalent hardware, so it
 should run on pretty much any cloud server as long as enough power is
-provided. If you find yourself running Mailu on small hardware, e.g.
-Raspberry Pi or other platforms based on ARM, you will probably find
-some support from `MFAshby's fork`_.
+provided. For non x86 machines, see :ref:`rpi_build`
 
 You are free to choose any operating system that runs Docker (>= 1.11),
 then chose between various flavors including Docker Compose, Kubernetes
@@ -34,7 +32,6 @@ You should also have at least a DNS hostname and a DNS name for receiving
 emails. Some instructions are provided on the matter in the article
 :ref:`dns_setup`.
 
-.. _`MFAshby's fork`: https://github.com/MFAshby/Mailu
 
 Pick a Mailu version
 --------------------