fix: add plugins in the image

.docker/app/startup.sh

@@ -47,6 +47,14 @@ if [ -z $SKIP_RSYNC_ON_STARTUP ]; then
 		sudo -u app rsync -a --no-owner --delete \
 			$SRC_DIR/plugins.local/nginx_xaccel \
 			$DST_DIR/plugins.local/nginx_xaccel
+
+		sudo -u app rsync -a --no-owner --delete \
+			$SRC_DIR/plugins.local/mastodon \
+			$DST_DIR/plugins.local/mastodon
+
+		sudo -u app rsync -a --no-owner --delete \
+			$SRC_DIR/plugins.local/mailer_smtp \
+			$DST_DIR/plugins.local/mailer_smtp
 	fi
 else
 	echo "warning: working copy in $DST_DIR won't be updated, make sure you know what you're doing."