Start to build Forez main route

lib/models/config.dart

@@ -1,6 +1,7 @@
 import 'dart:ui';
 
 import 'package:comunic/ui/routes/tour_route.dart';
+import 'package:flutter/material.dart';
 import 'package:meta/meta.dart';
 
 /// Application configuration model
@@ -15,6 +16,8 @@ class Config {
   final String apiServerUri;
   final bool apiServerSecure;
   final String clientName;
+
+  // Theme customization
   final Color splashBackgroundColor;
   final Color primaryColor;
   final Color primaryColorDark;
@@ -24,6 +27,9 @@ class Config {
   // Entries for the welcome tour
   final TourEntriesBuilder toursEntriesBuilder;
 
+  // Custom main application route
+  final Widget Function(BuildContext) mainRouteBuilder;
+
   const Config({
     @required this.apiServerName,
     @required this.apiServerUri,
@@ -35,6 +41,7 @@ class Config {
     this.appName = "Comunic",
     this.appQuickDescription,
     this.toursEntriesBuilder,
+    this.mainRouteBuilder,
   })  : assert(apiServerName != null),
         assert(apiServerUri != null),
         assert(apiServerSecure != null),