Add a link to MFAshby's fork

docs/setup.rst

@@ -17,6 +17,12 @@ long-term professional support, you should probably turn to them instead.
 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`_.
+
 You are free to choose any operating system that runs Docker (>= 1.11),
 then chose between various flavors including Docker Compose, Kubernetes
 and Rancher.
@@ -28,6 +34,8 @@ 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
 [Setup your DNS](dns).
 
+.. _`MFAshby's fork`: https://github.com/MFAshby/Mailu
+
 Pick a Mailu version
 --------------------