Export postgresql port to host

Updated docker-compose.yml so that it allows to run GitLabIT against the created containers

src/docker/docker-compose.yml

@@ -2,6 +2,8 @@ postgresql:
   container_name: docker-postgresql
   restart: always
   image: sameersbn/postgresql:9.5-1
+  ports:
+    - "5432:5432"
   environment:
     - DB_USER=gitlab
     - DB_PASS=password