More precision about the log directory permissions

Author: javiereguiluz

setup/file_permissions.rst

@@ -11,9 +11,7 @@ was writable. But that is no longer true! In Symfony 4, everything works automat
   is ``0``), as long as you run ``php bin/console cache:warmup``, no cache files
   will need to be written to disk at runtime.
 
-.. note::
-
-    If you decide to store log files on disk, you *will* need to make sure your
-    logs directory (e.g. ``var/log/``) is writable by your web server user and
-    terminal user. One way this can be done is by using ``chmod -R 777 var/log/``.
-    Be aware that your logs are readable by any user on your production system.
+* In all environments, the log directory (``var/log/`` by default) must exist
+  and be writable by your web server user and terminal user. One way this can
+  be done is by using ``chmod -R 777 var/log/``. Be aware that your logs are
+  readable by any user on your production system.