added mysql to docker-compose.yml, updated submodules

docker-compose.yml

@@ -8,6 +8,8 @@ services:
       - /app/node_modules
     ports:
       - "3000:3000"
+    depends_on:
+      - database
 
   frontend:
     build:
@@ -21,3 +23,18 @@ services:
     depends_on:
       - backend
 
+  database:
+    image: mysql:8
+    restart: always
+    environment:
+      MYSQL_ROOT_PASSWORD: root
+      MYSQL_DATABASE: ritzenbergen
+      MYSQL_USER: app
+      MYSQL_PASSWORD: pwd
+    ports:
+      - "3306:3306"
+    volumes:
+      - mysql_data:/var/lib/mysql
+
+volumes: 
+  mysql_data: