simple_form associations and mongomapper

Question

I get this message when I try to add an association in my form:

Association :role not found

role.rb

...
many :users

key :name, String
key :description, String
...

user.rb

...
belongs_to :role

key :username, String
key :password, String
key :password_salt, String
key :email, String
key :first_name, String
key :last_name, String
key :active, Boolean, :default => true
...

form

<%= simple_form_for [:admin, @user] do |f| %>
  <%= f.input :username %>
  <%= f.input :email %>
  <%= f.input :first_name %>
  <%= f.input :last_name %>
  <%= f.input :password %>
  <%= f.association :role %>
  <%= f.input :active, :as => :boolean %>
  <%= f.button :submit %>
<% end %>

Has anyone used associations in simple_form with mongomapper?

Answer 1

For now, simple_form only works with active_record. But if you want to use it with any active_model compatible library, make sure that you have passed the collection to association helper. eg.:

<%= f.association :role, :collection => Role.all %>

But I think that mongomapper is not an active_model compatible library.