diff --git a/examples/rubyonrails/.test.sh b/examples/rubyonrails/.test.sh
index a055c6b04..1c701bfa9 100755
--- a/examples/rubyonrails/.test.sh
+++ b/examples/rubyonrails/.test.sh
@@ -2,9 +2,9 @@
 set -ex
 
 pushd blog
-    wait_for_port 5100
+    wait_for_port 3000
     rails db:create
-    curl -s http://localhost:5100/ | grep "version"
+    curl -s http://localhost:3000/ | grep "version"
 popd
 
 # make sure puma was compiled with ssl
diff --git a/examples/rubyonrails/devenv.nix b/examples/rubyonrails/devenv.nix
index 1273110ca..4586b3f9d 100644
--- a/examples/rubyonrails/devenv.nix
+++ b/examples/rubyonrails/devenv.nix
@@ -16,7 +16,7 @@
   enterShell = ''
     if [ ! -d "blog" ]; then
       gem install rails
-      rails new blog -d=postgresql
+      rails new blog --database=postgresql --force
     fi
     export PATH="$DEVENV_ROOT/blog/bin:$PATH"
     pushd blog
diff --git a/package.nix b/package.nix
index 6a6cf019d..54651a6c5 100644
--- a/package.nix
+++ b/package.nix
@@ -4,11 +4,12 @@ pkgs.rustPlatform.buildRustPackage {
   pname = "devenv";
   version = "1.0.0";
 
-  src = builtins.path {
-    path = ./.;
-    filter = path: type:
-      path != "Cargo.lock" || path != "Cargo.toml" || path != "src/devenv";
-  };
+  src = pkgs.lib.sourceByRegex ./. [
+    "Cargo.toml"
+    "Cargo.lock"
+    "devenv(/\.*)?"
+    "devenv-run-tests(/\.*)?"
+  ];
 
   cargoLock = {
     lockFile = ./Cargo.lock;
diff --git a/src/modules/services/postgres.nix b/src/modules/services/postgres.nix
index 4dfef8c68..847380764 100644
--- a/src/modules/services/postgres.nix
+++ b/src/modules/services/postgres.nix
@@ -56,7 +56,10 @@ let
         cfg.initialDatabases)
     else
       lib.optionalString cfg.createDatabase ''
-        echo "CREATE DATABASE ''${USER:-$(id -nu)};" | psql --dbname postgres'';
+        psql --dbname postgres << EOF
+        CREATE DATABASE "''${USER:-$(id -nu)}";
+        EOF
+      '';
 
   runInitialScript =
     if cfg.initialScript != null then