run migrations automatically on backend startup (AUTO_MIGRATIONS)

Add a migrate.sh config (ported from lasuite-docs) that the backend
entrypoint runs when AUTO_MIGRATIONS=true (default). It loads secrets,
waits for the DB, and idempotently applies pending migrations via
'migrate --check' then 'migrate --noinput'. The manual 'abra app cmd
backend migrate' now delegates to the same script.

compose.yml

@@ -118,9 +118,11 @@ services:
     user: ${DOCKER_USER:-1000}
     image: lasuite/drive-backend:v0.19.0
     command: [ "gunicorn", "-c", "/usr/local/etc/gunicorn/drive.py", "drive.wsgi:application" ]
-    entrypoint: [ "/abra-entrypoint.sh", "/usr/local/bin/entrypoint" ]
+    entrypoint: >
+      sh -c "if [ \"$$AUTO_MIGRATIONS\" = \"true\" ]; then /migrate.sh; fi && exec /abra-entrypoint.sh /usr/local/bin/entrypoint \"$$@\"" --
     environment:
       <<: [ *common-env, *postgres-env ]
+      AUTO_MIGRATIONS: "${AUTO_MIGRATIONS:-true}"
     networks:
       - backend
     depends_on:
@@ -129,6 +131,9 @@ services:
       - source: abra_entrypoint
         target: /abra-entrypoint.sh
         mode: 0555
+      - source: migrate
+        target: /migrate.sh
+        mode: 0555
     secrets:
       - django_sk
       - django_sp
@@ -405,6 +410,9 @@ configs:
   abra_entrypoint:
     name: ${STACK_NAME}_entrypoint_${ABRA_ENTRYPOINT_VERSION}
     file: abra-entrypoint.sh
+  migrate:
+    name: ${STACK_NAME}_migrate_${MIGRATE_VERSION}
+    file: migrate.sh
   onlyoffice_conf:
     name: ${STACK_NAME}_onlyoffice_conf_${ONLYOFFICE_CONF_VERSION}
     file: onlyoffice-config.json.tmpl