Data model for Rails app using rails_erd

datamodel.rake

namespace :datamodel do
  desc 'Generates data model in erd.pdf'
    task :generate do
    #say 'Loading application environment...'
    Rake::Task[:environment].invoke
      
    require 'rails_erd/diagram/graphviz'
    #say 'Loading all models...'
    Rails.application.eager_load!
    ::Rails::Engine.subclasses.map(&:instance).map {|e| e.class.eager_load!}
    #say 'Generating erd.pdf...'
    RailsERD::Diagram::Graphviz.create
  end
end