[Misc] Added an assumption section in the README

README.md

@@ -7,6 +7,13 @@ branch/tag you use).
 
 All source files are under the LGPL 2.1 license.
 
+# Assumptions
+
+The goal is to provide a production-ready XWiki system running in Docker. This why:
+* The OS is based on Debian and not on some smaller-footprint distribution like Alpine
+* Several containers are used with Docker Compose: one for the DB and another for XWiki + Servlet container. This 
+  allows the ability to run them on different machines for example. 
+
 # Using
 
 You should first install [Docker](https://www.docker.com/) on your machine.