rails g model Person name:string
presence validates
rails g migration AddTermsOfServiceToPerson terms_of_service:text
acceptance validates helper

It can receive an :accept option, which determines the value that will be considered acceptance. It defaults to "1"
change :accept option of acceptance
validates_associated validates helper

Don't use validates_associated on both ends of your associations. They would call each other in an infinite loop.
confirmation validates helper

confirm an email address
exclusion validates helper

The exclusion helper has an option :in that receives the set of values that will not be accepted for the validated attributes
format validates helper
inclusion validates helper
length validates helper

minimum, maximum, in, is
maximum too_long %{count}
minimum too_short %{count}
numericality validates helper

options:
only_interger
greater_than
greater_than_or_equal_to
equal_to
less_than
less_than_or_equal_to
odd
even
presence validates helper
absence validates helper
uniqueness validates helper
some common validation options
some validation errors
Merge pull request #10 from hxx/ActiveRecordValidations

merged!