diff --git a/README.md b/README.md
index 078589d56291a070f4cb68ad0c7d72cf8c3839d4..693dd7e42b79ab29ad308f1b705389aedb6ef0b7 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,7 @@ Make sure you have [docker-compose](http://docs.docker.com/compose/install/) ins
 ```
 git clone https://github.com/indiehosters/discourse.git
 cd discourse
+echo "POSTGRES_USER=discourse" > env
 docker-compose run app bash -c "sleep 3 && rake db:migrate assets:precompile"
 docker-compose up
 ```