Update README.md

Author: dedok

README.md

@@ -13,9 +13,10 @@ About Tarantool: http://tarantool.org
 
 About upstream: http://nginx.org/en/docs/http/ngx_http_upstream_module.html#upstream
 
-Docker images
+## Docker images
 
 Nginx upstream module - https://hub.docker.com/r/tarantool/tarantool-nginx
+
 Tarantool - https://hub.docker.com/r/tarantool/tarantool
 
 ## Status