add charset messages

Author: andersonjoseph

lib/messages.js

@@ -12,6 +12,9 @@ module.exports = {
 	stringContains: "The '{field}' field must contain the '{expected}' text!",
 	stringEnum: "The '{field}' field does not match any of the allowed values!",
 	stringNumeric: "The '{field}' field must be a numeric string",
+	stringAlpha: "The '{field}' field must be an alphabetic string",
+	stringAlphanum: "The '{field}' field must be an alphanumeric string",
+	stringAlphadash: "The '{field}' field must be an alphadash string",
 
 	number: "The '{field}' field must be a number!",
 	numberMin: "The '{field}' field must be greater than or equal to {expected}!",