Unable to assign output of FactoryGirl.create(:user) to a :user variable when factory uses 'sequence'

Unable to assign output of FactoryGirl.create(:user) to a :user variable
when factory uses 'sequence'

I'm following Michael Hartl's great book on Ruby on Rails(rails 3.2
version). I'm having some problems in section 9.3.3. Pagination.
After I modified my factory at spec/factories.rb using sequence like
this(note that I have the previous version commented out):
FactoryGirl.define do
#factory :user do
# name "Michael Hartl"
# email "michael@example.com"
# password "foobar"
# password_confirmation "foobar"