Add an authz table.
pep8.
Add a method for checking evaluating authorization.
Add an add_authorization api func.
Fix the authorized check.
Use utcnow, not tz now.
Use python-arrow to return a relative date for expiration.
Replace a few more instances of .now with .utcnow.
Merge pull request #29 from fedora-infra/feature/authz

Add an authz table.