If you want to stick with Visual Studio, you can always use the Ruby in Steel plugin by Sapphire Steel. The best traditional IDE for Ruby is probably NetBeans, it even has a special stripped-down Ruby Edition.
However, note that unlike less expressive languages like Java, C# or VB.NET, you can not only get by, but even be more productive with a good text editor than with a traditional static IDE. IDEs like NetBeans, Eclipse and Visual Studio are designed with static languages in mind, and trying to force Ruby into that ecosystem is just unnatural.
There is a nice article on The Best Environment for Rails on Windows by Fabio Akita that you might want to read. While I don’t agree with everything he writes (mostly because I don’t use Rails), it is a pretty good introduction of how you might want to setup a development environment specifically for Rails.