Mine

khaled@suse:~/ruby.src/depot> rake db:migrate
(in /home/khaled/ruby.src/depot)
== AddPrice: migrating ========================================================
-- add_column(:products, :price, :decimal, {:default=>0, :precision=>8, :scale=>2})
rake aborted!
You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occured while evaluating nil.[]

(See full trace by running task with --trace)