Speed up local platform tests by ramfs

Author: janedbal

tests/Platform/docker/docker-compose.yml

@@ -9,6 +9,10 @@ services:
         environment:
             MYSQL_ROOT_PASSWORD: secret
             MYSQL_DATABASE: foo
+        volumes:
+            -
+                type: tmpfs
+                target: /var/lib/mysql
 
     pgsql:
         image: postgres:13
@@ -18,6 +22,10 @@ services:
             POSTGRES_PASSWORD: secret
             POSTGRES_USER: root
             POSTGRES_DB: foo
+        volumes:
+            -
+                type: tmpfs
+                target: /var/lib/postgresql/data
 
     php80:
         depends_on: [mysql, pgsql]