./README.md in rack-push-notification-0.5.0 vs ./README.md in rack-push-notification-0.5.1

@@ -25,10 +25,10 @@
 
 **It is strongly recommended that you use `Rack::PushNotification` in conjunction with some sort of Rack authentication middleware, so that the administration endpoints are not accessible without some form of credentials.**
 
 ## Example Usage
 
-Rack::PushNotification can be run as Rack middleware or as a single web application. All that is required is a connection to a Postgres database. You must define this with the environment variable `DATABASE_URL`. For rails, use the `rails-database-url` to define this from the `database.yml`.
+Rack::PushNotification can be run as Rack middleware or as a single web application. All that is required is a connection to a Postgres database. You must define this with the environment variable `DATABASE_URL`. For rails, use the [`rails-database-url`](https://github.com/glenngillen/rails-database-url) gem to define this from the `database.yml`.
 
 ### config.ru
 
 ```ruby
 require 'bundler'