README: add postgresql commands to migration section

Signed-off-by: NeroBurner <pyro4hell@gmail.com>

README.md

@@ -347,16 +347,28 @@ You're already using Nextcloud and want to switch to docker? Great! Here are som
 
 1. Define your whole Nextcloud infrastructure in a `docker-compose` file and run it with `docker-compose up -d` to get the base installation, volumes and database. Work from there.
 2. Restore your database from a mysqldump (nextcloud\_db\_1 is the name of your db container)
-```console
+  - To import from a MySQL dump use the following commands
-docker cp ./database.dmp nextcloud_db_1:/dmp
+    ```console
-docker-compose exec db sh -c "mysql -u USER -pPASSWORD nextcloud < /dmp"
+    docker cp ./database.dmp nextcloud_db_1:/dmp
-docker-compose exec db rm /dmp
+    docker-compose exec db sh -c "mysql -u USER -pPASSWORD nextcloud < /dmp"
-```
+    docker-compose exec db rm /dmp
+    ```
+  - To import from a PostgreSQL dump use to following commands
+    ```console
+    docker cp ./database.dmp nextcloud_db_1:/dmp
+    docker-compose exec db sh -c "psql -U USER --set ON_ERROR_STOP=on nextcloud < /dmp"
+    docker-compose exec db rm /dmp
+    ```
 3. Edit your config.php
   1. Set database connection
-  ```php
+     - In case of MySQL database
-  'dbhost' => 'db:3306',
+      ```php
-  ```
+      'dbhost' => 'db:3306',
+      ```
+     - In case of PostgreSQL database
+      ```php
+      'dbhost' => 'db:5432',
+      ```
   2. Make sure you have no configuration for the `apps_paths`. Delete lines like these
   ```diff
   - "apps_paths" => array (