Update docker compose file to use named volumes

Author: richardboehme

.gitignore

@@ -12,6 +12,5 @@
 Gemfile.lock
 docker-compose.yml
 /test/database.yml
-/data/
 /log/*
 !/log/.keep

docker-compose.yml.example

@@ -1,5 +1,3 @@
-version: "3.8"
-
 services:
   postgresql:
     image: postgres:latest
@@ -10,7 +8,7 @@ services:
     ports:
       - "5432:5432"
     volumes:
-      - ./data/postgres:/var/lib/postgresql/data
+      - postgres_data:/var/lib/postgresql/data
 
   mysql:
     image: mariadb
@@ -21,4 +19,8 @@ services:
     ports:
       - "3306:3306"
     volumes:
-      - ./data/mysql:/var/lib/mysql
+      - mysql_data:/var/lib/mysql
+
+volumes:
+  postgres_data:
+  mysql_data: