Added drill controllers test
Make responsiveness of bootstrap come back.

Seriously, why on earth does that flash card form bug happen?
Stubbed out things for examples MVC
Made users authable and sign-in/out kinda works
Nuke zhuyin from orbit (because it is annoying)
Empty users fixture

It breaks the one test I have :sweat_smile:
Actually make login/logout work

In short, I'm a lying herp-derp.

Seed user is "laoshi@example.com" with password "laoshi"
Added user method to flash cards and examples
Add User#owns? <item>
Added some example auth restrictions on pages

Changes:
* Add/Edit only shows if @user.owns? teachable
* Trying to access drill#edit rejects if you don't own the drill
Fix sign in bar's links