Add shared network configuration for services in docker-compose file

docker-compose.yml

@@ -7,6 +7,8 @@ services:
     env_file:
       - ./gateway.env
     restart: on-failure
+    networks:
+      - rheinsw-net
 
   server:
     image: registry.boomlab.party/rheinsw/rheinsw-mono-repo/server
@@ -16,6 +18,8 @@ services:
     env_file:
       - ./server.env
     restart: on-failure
+    networks:
+      - rheinsw-net
 
   frontend:
     image: registry.boomlab.party/rheinsw/rheinsw-mono-repo/frontend
@@ -23,3 +27,9 @@ services:
     ports:
       - "5100:3000"
     restart: on-failure
+    networks:
+      - rheinsw-net
+
+networks:
+  rheinsw-net:
+    driver: bridge