Custom date validation to prevent the save of default date in Rails Activerecord with validates_with

extensions.rb

Place this file in your config/initializers

class CheckDate < ActiveModel::Validator
#Sat Jan 01 00:00:00 UTC 2000 is the default date that rails store

 def validate(record)
  	if record.start_time == "Sat Jan 01 00:00:00 UTC 2000".to_date
  	 record.errors[:base] << "This is a invalid date"
  	end
  end
end

my_model.rb

 Schema entry
    #t.time     "start_time",      :null => false
    #t.datetime "created_at"
    #t.datetime "updated_at"


class MyModel < ActiveRecord::Base
  validates_with CheckDate
end