Railsで active_admin deviseのデバッグログの手順
操作手順：
1.gem
gem 'activeadmin’,github: 'activeadmin’
gem 'devise’
2.install
rails g active_admin:install
The generator adds these core files, among others:
app/admin/dashboard.rb
app/assets/javascripts/active_admin.js.coffee
app/assets/stylesheets/active_admin.css.scss
config/initializers/active_admin.rb
3.migrate
rake db:migrate
rails server
4.config initializers active_admin,devise
5.create another model
rails g devise User
rake db:migrate