class ActiveUtils::Validateable::Errors

This hash keeps the errors of the object

def add(field, error) 

def add(field, error)
  self[field] << error
end

def add_to_base(error) 

def add_to_base(error)
  add(:base, error)
end

def count 

def count
  size
end

def each_full 

def each_full
  full_messages.each { |msg| yield msg }
end

def empty? 

def empty?
  all? { |k, v| v && v.empty? }
end

def full_messages 

def full_messages
  result = []
  self.each do |key, messages|
    next if messages.blank?
    if key == 'base'
      result << "#{messages.first}"
    else
      result << "#{key.to_s.humanize} #{messages.first}"
    end
  end
  result
end

def initialize(base) 

def initialize(base)
  super() { |h, k|  h[k] = [] ; h[k] }
  @base = base
end

def on(field)

we return an empty string
if more than one error is available we will only return the first. If no error is available
returns a specific fields error message. 
def on(field)
  self[field].to_a.first
end