ErdKeeper is a gem that outputs ER diagram by setting yaml.

The output of ER diagram is realized by wrapping call of rails-erd.

This gem generate a diagram based on your application's Active Record models.

Add this line to your application's Gemfile:

gem 'erd-keeper'

And then execute:

$ bundle

Create configuration file (Write your application's Active Record models):

diagrams:
  tweet:
    - User
    - Micropost
  all:
    - User
    - Micropost
    - Relationship

And then execute:

$ bundle exec erd-keeper --input="config/erd-keeper.yml" --output="./"

• --input : Write the path of the configuration file.
• --output : Write the path of the output ER diagram.

The gem is available as open source under the terms of the MIT License.