[#14] Add General Law Information

Fixes #14 

Kinda tempted to put `identity_card_number` in `GeneralLaw` too.
Using `f.text_field` etc uses the object class to name the attributes, so `f.label :email` renders as `<input id="user_email" name="user[email]"`, regardless of the instance variable passed in to `form_for`. I couldn't get the nested attributes to work without using the resource-oriented style form – don't know whether its a bug in Rails, something I was doing, or something elsewhere in the app that was interfering. I expect there's a way to make it work, but I figure we'd end up creating more of a mess and just doing it properly would be the better thing to do.