Update backend docker-compose (format)

backend/docker-compose.yml

@@ -1,3 +1,4 @@
+---
 version: 3.4
 services:
   web:
@@ -5,16 +6,10 @@ services:
     build:
       context: ./docker
       dockerfile: Dockerfile
-        depends_on:
-            - twitter_clone_mysql
-        volumes:
-            - .:/var/www/html:Z
-        ports:
-            - 8080:8080
-        networks:
-            - sail
-        depends_on:
-            - mysql
+    volumes: [.:/var/www/html:Z]
+    ports: [8080:8080]
+    networks: [sail]
+    depends_on: [mysql]
   mysql:
     container_name: twitter_clone_mysql
     image: mysql
@@ -22,13 +17,9 @@ services:
     environment:
       MYSQL_DATABASE: twitter
       MYSQL_ALLOW_EMPTY_PASSWORD: 1
-        ports:
-            - 3306:3306
-        volumes:
-            - dbdata:/var/lib/mysql
-            - ./docker/mysqld.conf:/etc/mysql/my.cnf
-        networks:
-            - sail
+    ports: [3306:3306]
+    volumes: [dbdata:/var/lib/mysql, ./docker/mysqld.conf:/etc/mysql/my.cnf]
+    networks: [sail]
 networks:
   sail:
     driver: bridge