Undefined method "add_reference"

rubyonrails-talk
1

Greetings,

I try to add a foreign key in one of my rails migrations in the following way:

def self.up          add_reference :categories, :items end

This, strangely, leads to the following error during the migration:

-- add_reference(:categories, :items) rake aborted! undefined method `add_reference' for #

In the same way fails the code:

def self.up   change_table :categories do |t|       t.references :items   end end

I recently upgraded to Rails 2.1.2, if this is relevant to my case. Does anyone have any pointers on how to solve this problem?

Thanks in advance!