ActiveAdmin - uninitialized constant AdminUser

Question

I'm getting an error while trying to run my app, having recently installed ActiveAdmin. It was working fine, but, after idling for a while, suddenly it isn't!

In my gem file:

gem 'activeadmin'

In my routes:

  devise_for :admin_users, ActiveAdmin::Devise.config
  ActiveAdmin.routes(self) 

And in my admin_user.rb

ActiveAdmin.register AdminUser do     
  index do                            
    column :email                     
    column :current_sign_in_at        
    column :last_sign_in_at           
    column :sign_in_count             
    default_actions                   
  end   etc....

The error when trying to run:

NameError: uninitialized constant AdminUser
~/Desktop/Sites/Fleetnation/app/admin/admin_user.rb:1:in `<top (required)>'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.11/lib/active_support/inflector/methods.rb:230:in `block in constantize'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.11/lib/active_support/inflector/methods.rb:229:in `each'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.11/lib/active_support/inflector/methods.rb:229:in `constantize'
...

Anyone got any ideas? Would be much appreciated.

Solution 1

Try restarting rails server. Had similar problems which cleared up after a restart.

Solution 2

This error will be thrown any time your model has an erroneous association in it. If you changed any associations, but forget to update your model's file, you will get this error.

Double check your model files. Open active admin locally to see what error it gives you (localhost:3000/admin). It will usually say uninitialized constant MyModel:MyBadAssociation, so helps you diagnose the error.

Comments

[Benji Lanyado]

Nope... doesn't fix it I'm afraid!

[Nate Beers]

No matter how many times I have run into this issue, I always forget to restart the server after installing a new gem. Then, I see an answer like this and I remember. Thanks.

[Jayant Bhawal]

I can't believe that this was the fix. +1 for reminding that fixes can be simple too at times.