Schemapper
Schemapper is a database-agnostic tool to visualize Rails 3.0+ schemas using D3. Schemapper does this by walking your models directly to obtain their associations, table names, and attributes.
Screen Shot

Installation
No need to add schemapper to your Gemfile. Instead, just install it:
$ gem install schemapper
Usage
After installing it, just run the following command from the root of your Rails app:
$ schemapper
Contributing
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request