gistfile1.txt

First, install graphviz - http://www.graphviz.org/Download..php -- 
it is available for multiple platforms and is easy to install.

Secondly, run a:

   1  gem install railroad

And Railroad and its dependencies are installed. Railroad is capable of visualizing model relationships,
 controllers, and more. Check the railroad site at http://railroad.rubyforge.org/ for great examples 
such as Typo visualized and other sick visualizations. Once you have these installed,

   1  railroad -M -a | neato -Tpng > models.png

is all you need to produce a png of your models in a nice clean ERD style format.