old_contents: var errorMessages = {
  	required: '%s field is required.',
  	matches: '%s field doesn\'t match %s field.',
  	minLength: '%s field must a have a minimum length of %s.',
  	maxLength: '%s field mustn\'t exceed a maximum length of %s.',
  	exactLength: '%s field must have an exact length of %s.',
  	greaterThan: '%s field must be greater than %s.',
  	lessThan: '%s field must be less than %s.',
  	regex: '%s field isn\'t valid.',
  	alpha: '%s field must contain only alphabetical characters.',
  	alphaNumeric: '%s field must contain only alphabetical characters and/or numbers.',
  	alphaDash: '%s field must contain only alphabetical characters, numbers and/or dashes.',
  	numeric: '%s field must contain only numbers.',
  	integer: '%s field must contain only integer numbers.',
  	decimal: '%s field must contain only decimal numbers.',
  	natural: '%s field must contain only integer number that is greater than or equal to 0.',
  	naturalNoZero: '%s field must contain only integer number that is greater than 0.',
  	email: '%s field must contain a valid email address.',
  	list: '%s isn\'t a valid list.',
      minListLength: '%s should have a minimum length of %s.',
      maxListLength: '%s should have a maximum length of %s.'
  };
  
  module.exports = errorMessages;
  
new_contents: var errorMessages = {
  	required: '%s field is required.',
  	matches: '%s field doesn\'t match %s field.',
  	minLength: '%s field must a have a minimum length of %s.',
  	maxLength: '%s field mustn\'t exceed a maximum length of %s.',
  	exactLength: '%s field must have an exact length of %s.',
  	greaterThan: '%s field must be greater than %s.',
  	lessThan: '%s field must be less than %s.',
  	regex: '%s field isn\'t valid.',
  	alpha: '%s field must contain only alphabetical characters.',
  	alphaNumeric: '%s field must contain only alphabetical characters and/or numbers.',
  	alphaDash: '%s field must contain only alphabetical characters, numbers and/or dashes.',
  	numeric: '%s field must contain only numbers.',
  	integer: '%s field must contain only integer numbers.',
  	decimal: '%s field must contain only decimal numbers.',
  	natural: '%s field must contain only integer number that is greater than or equal to 0.',
  	naturalNoZero: '%s field must contain only integer number that is greater than 0.',
  	email: '%s field must contain a valid email address.',
  	list: '%s isn\'t a valid list.',
      minListLength: '%s should have a minimum length of %s.',
      maxListLength: '%s should have a maximum length of %s.',
  	date: '%s should be in a good date shape.',
  	beforeDate: '%s should be eariler than %s.',
  	afterDate: '%s should be later than %s.'
  };
  
  module.exports = errorMessages;
  
subject: add error messages for date validation