added db migration part to the docs

README.md

@@ -70,6 +70,14 @@ $ docker run -p 6379:6379 redis:alpine redis
 $ docker run -p 80:80 --link redis:redis wallabag/wallabag
 ```
 
+## DB migration
+
+If there is a version upgrade that needs a database migration, you should start the container with the new image and run the migration command.
+
+```
+$ docker exec -t wallabag /var/www/wallabag/bin/console doctrine:migrations:migrate --env=prod --no-interaction
+```
+
 ## docker-compose
 
 It's a good way to use [docker-compose](https://docs.docker.com/compose/). Example:

root/etc/ansible/entrypoint.yml

@@ -122,12 +122,6 @@
         chdir: /var/www/wallabag
       notify: chown dir
 
-    - name: run migration
-      shell: php bin/console doctrine:migrations:migrate --env=prod
-      args:
-        chdir: /var/www/wallabag
-      notify: chown dir
-
     - name: chown dir
       file:
         path=/var/www/wallabag