Add Warden dependency
Create token model + table
Add Token.authenticate
Add AccessToken strategy for Warden
Simplify exception to error mapping
Handle Authentication + error response
Display error on missing token
Add warden test helpers to api spec helpers
Fix events endpoints spec for authentication
Check authentication for singular event
Spec auth for non-existent resources

And DRY up specs a little
Prepare people endpoint spec for authorization
Add authorization check for people endpoint
Merge pull request #50 from cvut/access_token

Simple token authentication