Split the environment file into sections

.env

@@ -4,8 +4,9 @@
 # these few settings must however be configured before starting the mail
 # server and require a restart upon change.
 
-# Project name
-COMPOSE_PROJECT_NAME=freeposte
+###################################
+# Common configuration variables
+###################################
 
 # Set this to the path where Freeposte data and configuration is stored
 ROOT=/freeposte
@@ -13,9 +14,6 @@ ROOT=/freeposte
 # Freeposte version to run (stable, 1.0, 1.1, etc. or testing)
 VERSION=stable
 
-# Set this to enable debugging globally
-DEBUG=False
-
 # Set to a randomly generated 16 bytes string
 SECRET_KEY=ChangeMeChangeMe
 
@@ -31,12 +29,23 @@ HOSTNAME=mail.freeposte.io
 # Postmaster local part (will append the main mail domain)
 POSTMASTER=admin
 
+# Docker-compose project name, this will prepended to containers names.
+COMPOSE_PROJECT_NAME=freeposte
+
+###################################
+# Optional features
+###################################
+
 # Choose which frontend Web server to run if any (value: nginx, none)
 FRONTEND=none
 
 # Choose which webmail to run if any (values: roundcube, none)
 WEBMAIL=none
 
+###################################
+# Mail settings
+###################################
+
 # Networks granted relay permissions, make sure that you include your Docker
 # internal network (default to 172.17.0.0/16)
 RELAYNETS=172.16.0.0/12
@@ -46,3 +55,10 @@ RELAYHOST=
 
 # Fetchmail delay
 FETCHMAIL_DELAY=600
+
+###################################
+# Developers
+###################################
+
+# Set this to enable debugging globally
+DEBUG=False