Monthly Archives: June 2012

Rails namespaced models NameError uninitialized constant

I’m using rails v3.2.3

Using namespaced models, you should specify full class names for database associations to avoid this error.


class Assets::Resource < ActiveRecord::Base
  has_many :assets_resource_users, :class_name => “::Assets::ResourceUser”

class Assets::ResourceUser < ActiveRecord::Base
  belongs_to :asset_resource, :class_name => “::Assets::Resource”

Put :: at the beginning to specify the namespace from the root.

Also, you should set the foreign key on your associations, or rails gets confused.  For example, if you set up resource:references in the migration to create the ResourceUser above, it will create a column “resource_id”, but rails looks for “assets_resource_id” by default.

Adding a new sudo user to CentOs

Our new user will be called batman:

  1. groupadd admins
  2. adduser batman -G admins
  3. passwd batman
  4. visudo (this will open sudoers file in vim)
  5. Add this to the file:
    %admins     ALL=(ALL)     ALL

Any users in the group called ‘admins’ will be sudoers.  So additional users just need to be added to this group.