Adding empty configuration system.

I mostly followed @cg505's comment in #23.
Update db schema to match new configuration migration

Forgot to migrate, now I did.
Add model relationships between configuration and user

Since it's just one-to-one (right?), it should be pretty simple.
Merge branch 'v0.2.0' into user-configuration

This adds the "my account" link.
Change "My Account" link to redirect to user#edit instead of #show

This makes it easier to get to user configuration? Not sure.