Use a default env var selector

Added a method that provides:

* Easy defaults for secure ENV vars (pepper, secret key, etc) that don't
matter in dev/test
* Enforces that the value MUST be set in production or else the app
won't run (we don't want to accidentily use the defaults in production)
Added devise User model
Add Devise views

We'll be overriding most, if not all, of these.  So used the generator
to copy them over so contributors aren't searching for them later
Add basic devise nav
Create new account

Also creates the owner user
Fixed missing indexes

A few minor missing indexes.

For cleanliness and because the project is so early, I opted to make
this change inline.  That way there isn't an extra migration.  So a
'rake db:migrate:reset' is necessary.  If the project were any older, a
separate migration would be preferred, but this seems appropriate.
Removed misc comments

This was my commenting from a code approach I chose not to take
Merge pull request #11 from drewblas/add_account_creation

Add account creation