BUGSSS

Filter to .first when getting users so you don't have to get [0] every
time
Use the other new syntax. Pass in SHA512 to override SHA256 default
Test for nil instead of empty array since it's not an array any more
mongoid randomly requires explicit active_support. Came out of nowhere
Use the updated pbkdf2 gem because updating the same gem is hard guys
Add authentication and bugfixes

Add authentication route
Store the Hex value of a PBKDF2, because the string value can't be un-
stringed
Authenticate a user