Use HTML5 email input fields for emails
Fix typo
Explicitly join users and locations

Add an explicit location_id field to the users table and deprecate the
old denormed location string.

Some bonus features:
* Somewhat improved queries based on the new schema (even more
  improvements coming soon)
* Decent as_json on User, Location, Book and Donation
Drop index on ActiveAdmin resource type/id

rake db:migrate keeps wanting to make this change
Pre-select user locations on donate page

Improves query perf by avoiding multiple lookups for locations.