diff --git a/docker/entrypoints/rails.sh b/docker/entrypoints/rails.sh
index 3774a8b63..80dee70ba 100755
--- a/docker/entrypoints/rails.sh
+++ b/docker/entrypoints/rails.sh
@@ -8,8 +8,14 @@ rm -rf /app/tmp/cache/*
 
 echo "Waiting for postgres to become ready...."
 
-PGPASSWORD=$POSTGRES_PASSWORD
-PSQL="pg_isready -h $POSTGRES_HOST -p 5432 -U $POSTGRES_USERNAME"
+# Let DATABASE_URL env take presedence over individual connection params.
+if [ -z "$DATABASE_URL" ]; then
+  PGPASSWORD=$POSTGRES_PASSWORD
+  PSQL="pg_isready -h $POSTGRES_HOST -p 5432 -U $POSTGRES_USERNAME"
+else
+  PSQL="pg_isready -d $DATABASE_URL"
+fi
+
 until $PSQL
 do
   sleep 2;