title: Validations for Rails 4 Postgres Array
body: <p>Is it possible to use standard Rails validations with a Postgres array? I have a <code>service_area</code> column which accepts an array of zip codes. It works well enough, though when I try to use validations for numericality and length, the validators throw errors. Input such as <code>78702, 78704, 78705</code> gets the error messages <code>is not a number</code> and <code>is the wrong length</code>. It appears that Rails is trying to validate them as a string, rather than as an array of five digit zipcodes. Is there some way to inform the validator that it needs to parse the input as an array? Thanks!</p>