Environment variables in docker-compose section (#1316)

* Environment variables in docker-compose section

Docker-compose file in the example was missing database configuration environment variables of the app container, making the stack to use SQLite by default instead of the DB container.

Didn't add `NEXTCLOUD_ADMIN_*` variables since this addresses the DB being configured with SQLite. This still works setting up admin credentials on first NC run.

Signed-off-by: tetebueno <9064236+tetebueno@users.noreply.github.com>

* Fixing FPM version too.

Signed-off-by: tetebueno <9064236+tetebueno@users.noreply.github.com>

README.md

@@ -241,9 +241,14 @@ services:
       - 8080:80
     links:
       - db
+    restart: always
     volumes:
       - nextcloud:/var/www/html
-    restart: always
+    environment:
+      - MYSQL_PASSWORD=
+      - MYSQL_DATABASE=nextcloud
+      - MYSQL_USER=nextcloud
+      - MYSQL_HOST=db
 
 ```
 
@@ -280,9 +285,14 @@ services:
     image: nextcloud:fpm
     links:
       - db
+    restart: always
     volumes:
       - nextcloud:/var/www/html
-    restart: always
+    environment:
+      - MYSQL_PASSWORD=
+      - MYSQL_DATABASE=nextcloud
+      - MYSQL_USER=nextcloud
+      - MYSQL_HOST=db
 
   web:
     image: nginx