MAPG-203 restructure Docker stack

docker-compose.yml

@@ -1,14 +1,23 @@
 version: '3'
 services:
     app:
-        build: ./docker
+        build:
+            context: ./docker
+            dockerfile: Dockerfile-app
         ports:
             - 80:80
         volumes:
             - .:/var/www/mapguesser
-        links:
-            - 'mariadb'
-            - 'mail'
+    multi:
+        build:
+            context: ./docker
+            dockerfile: Dockerfile-multi
+        ports:
+            - 5000:5000
+            - 8090:8090
+            - 9229:9229
+        volumes:
+            - .:/var/www/mapguesser
     mariadb:
         image: mariadb:10.3
         ports: