Fix permissions in background to speedup container startup

docker/symfony/entrypoint.sh

@@ -32,9 +32,9 @@ fi
 
 # Fix permissions
 for d in var vendor assets public node_modules legacy log src; do
-    chown -R :www-data $base_dir/web_dev/$d
-    chmod -R g+w $base_dir/web_dev/$d
+    chown -R :www-data $base_dir/web_dev/$d &
+    chmod -R g+w $base_dir/web_dev/$d &
 done
-chown -R 999:999 $base_dir/web_dev/mysql
+chown -R 999:999 $base_dir/web_dev/mysql &
 
 apache2ctl -DFOREGROUND