AssociationTypeMismatch (Object expected, got HashWithIndifferentAccess) in Rails app

Question

I\'m getting a AssociationTypeMismatch Error and I\'m not sure where I\'m making a mistake. I\'m pretty new to Rails so I\'m guessing I\'m making some silly mistake. I\'ve check

Answer 1

it is:

attr_accessible :preference_attributes

and in your form:

<%= f.fields_for :preference_attributes do |builder| %>
...