JSON column for `value`

[blairanderson]

Hi there,

I have:

• converted my value column to postgres JSON
• commented out serialize :value, Hash inside SettingObject

Its working beautifully.

This setup allows me to query nested data inside of the settings value column http://edgeguides.rubyonrails.org/active_record_postgresql.html#json-and-jsonb

Is there any interest in having this as a pull request?

Do you have a preference for configuration since it requires a user migration?